Ubuntu Manpage: collectd.conf - Configuration for the system statistics collection daemon collectd

Provided by: collectd-core_5.5.1-1build2_amd64

NAME

       collectd.conf - Configuration for the system statistics collection daemon collectd

SYNOPSIS

         BaseDir "/var/lib/collectd"
         PIDFile "/run/collectd.pid"
         Interval 10.0

         LoadPlugin cpu
         LoadPlugin load

         <LoadPlugin df>
           Interval 3600
         </LoadPlugin>
         <Plugin df>
           ValuesPercentage true
         </Plugin>

         LoadPlugin ping
         <Plugin ping>
           Host "example.org"
           Host "provider.net"
         </Plugin>

DESCRIPTION

This config file controls how the system statistics collection daemon collectd behaves. The most
significant option is LoadPlugin, which controls which plugins to load. These plugins ultimately define
collectd's behavior. If the AutoLoadPlugin option has been enabled, the explicit LoadPlugin lines may be
omitted for all plugins with a configuration block, i.e. a "<Plugin ...>" block.

The syntax of this config file is similar to the config file of the famous Apache webserver. Each line
contains either an option (a key and a list of one or more values) or a section-start or -end. Empty
lines and everything after a non-quoted hash-symbol ("#") is ignored. Keys are unquoted strings,
consisting only of alphanumeric characters and the underscore ("_") character. Keys are handled case
insensitive by collectd itself and all plugins included with it. Values can either be an unquoted string,
a quoted string (enclosed in double-quotes) a number or a boolean expression. Unquoted strings consist of
only alphanumeric characters and underscores ("_") and do not need to be quoted. Quoted strings are
enclosed in double quotes ("""). You can use the backslash character ("\") to include double quotes as
part of the string. Numbers can be specified in decimal and floating point format (using a dot "." as
decimal separator), hexadecimal when using the "0x" prefix and octal with a leading zero (0). Boolean
values are either true or false.

Lines may be wrapped by using "\" as the last character before the newline. This allows long lines to be
split into multiple lines. Quoted strings may be wrapped as well. However, those are treated special in
that whitespace at the beginning of the following lines will be ignored, which allows for nicely
indenting the wrapped lines.

The configuration is read and processed in order, i.e. from top to bottom. So the plugins are loaded in
the order listed in this config file. It is a good idea to load any logging plugins first in order to
catch messages from plugins during configuration. Also, unless AutoLoadPlugin is enabled, the LoadPlugin
option must occur before the appropriate "<Plugin ...>" block.

GLOBAL OPTIONS

BaseDir Directory
Sets the base directory. This is the directory beneath all RRD-files are created. Possibly more
subdirectories are created. This is also the working directory for the daemon.

LoadPlugin Plugin
Loads the plugin Plugin. This is required to load plugins, unless the AutoLoadPlugin option is
enabled (see below). Without any loaded plugins, collectd will be mostly useless.

Only the first LoadPlugin statement or block for a given plugin name has any effect. This is useful
when you want to split up the configuration into smaller files and want each file to be "self
contained", i.e. it contains a Plugin block and then appropriate LoadPlugin statement. The downside
is that if you have multiple conflicting LoadPlugin blocks, e.g. when they specify different
intervals, only one of them (the first one encountered) will take effect and all others will be
silently ignored.

LoadPlugin may either be a simple configuration statement or a block with additional options,
affecting the behavior of LoadPlugin. A simple statement looks like this:

LoadPlugin "cpu"

Options inside a LoadPlugin block can override default settings and influence the way plugins are
loaded, e.g.:

<LoadPlugin perl>
Interval 60
</LoadPlugin>

The following options are valid inside LoadPlugin blocks:

Globals true|false
If enabled, collectd will export all global symbols of the plugin (and of all libraries loaded as
dependencies of the plugin) and, thus, makes those symbols available for resolving unresolved
symbols in subsequently loaded plugins if that is supported by your system.

This is useful (or possibly even required), e.g., when loading a plugin that embeds some
scripting language into the daemon (e.g. the Perl and Python plugins). Scripting languages
usually provide means to load extensions written in C. Those extensions require symbols provided
by the interpreter, which is loaded as a dependency of the respective collectd plugin. See the
documentation of those plugins (e.g., collectd-perl(5) or collectd-python(5)) for details.

By default, this is disabled. As a special exception, if the plugin name is either "perl" or
"python", the default is changed to enabled in order to keep the average user from ever having to
deal with this low level linking stuff.

Interval Seconds
Sets a plugin-specific interval for collecting metrics. This overrides the global Interval
setting. If a plugin provides own support for specifying an interval, that setting will take
precedence.

AutoLoadPlugin false|true
When set to false (the default), each plugin needs to be loaded explicitly, using the LoadPlugin
statement documented above. If a <Plugin ...> block is encountered and no configuration handling
callback for this plugin has been registered, a warning is logged and the block is ignored.

When set to true, explicit LoadPlugin statements are not required. Each <Plugin ...> block acts as if
it was immediately preceded by a LoadPlugin statement. LoadPlugin statements are still required for
plugins that don't provide any configuration, e.g. the Load plugin.

CollectInternalStats false|true
When set to true, various statistics about the collectd daemon will be collected, with "collectd" as
the plugin name. Defaults to false.

The following metrics are reported:

"collectd-write_queue/queue_length"
The number of metrics currently in the write queue. You can limit the queue length with the
WriteQueueLimitLow and WriteQueueLimitHigh options.

"collectd-write_queue/derive-dropped"
The number of metrics dropped due to a queue length limitation. If this value is non-zero, your
system can't handle all incoming metrics and protects itself against overload by dropping
metrics.

"collectd-cache/cache_size"
The number of elements in the metric cache (the cache you can interact with using
collectd-unixsock(5)).

Include Path [pattern]
If Path points to a file, includes that file. If Path points to a directory, recursively includes all
files within that directory and its subdirectories. If the "wordexp" function is available on your
system, shell-like wildcards are expanded before files are included. This means you can use
statements like the following:

Include "/etc/collectd.d/*.conf"

Starting with version 5.3, this may also be a block in which further options affecting the behavior
of Include may be specified. The following option is currently allowed:

<Include "/etc/collectd.d">
Filter "*.conf"
</Include>

Filter pattern
If the "fnmatch" function is available on your system, a shell-like wildcard pattern may be
specified to filter which files to include. This may be used in combination with recursively
including a directory to easily be able to arbitrarily mix configuration files and other
documents (e.g. README files). The given example is similar to the first example above but
includes all files matching "*.conf" in any subdirectory of "/etc/collectd.d":

Include "/etc/collectd.d" "*.conf"

If more than one files are included by a single Include option, the files will be included in
lexicographical order (as defined by the "strcmp" function). Thus, you can e. g. use numbered
prefixes to specify the order in which the files are loaded.

To prevent loops and shooting yourself in the foot in interesting ways the nesting is limited to a
depth of 8 levels, which should be sufficient for most uses. Since symlinks are followed it is still
possible to crash the daemon by looping symlinks. In our opinion significant stupidity should result
in an appropriate amount of pain.

It is no problem to have a block like "<Plugin foo>" in more than one file, but you cannot include
files from within blocks.

PIDFile File
Sets where to write the PID file to. This file is overwritten when it exists and deleted when the
program is stopped. Some init-scripts might override this setting using the -P command-line option.

PluginDir Directory
Path to the plugins (shared objects) of collectd.

TypesDB File [File ...]
Set one or more files that contain the data-set descriptions. See types.db(5) for a description of
the format of this file.

Interval Seconds
Configures the interval in which to query the read plugins. Obviously smaller values lead to a higher
system load produced by collectd, while higher values lead to more coarse statistics.

Warning: You should set this once and then never touch it again. If you do, you will have to delete
all your RRD files or know some serious RRDtool magic! (Assuming you're using the RRDtool or
RRDCacheD plugin.)

MaxReadInterval Seconds
Read plugin doubles interval between queries after each failed attempt to get data.

This options limits the maximum value of the interval. The default value is 86400.

Timeout Iterations
Consider a value list "missing" when no update has been read or received for Iterations iterations.
By default, collectd considers a value list missing when no update has been received for twice the
update interval. Since this setting uses iterations, the maximum allowed time without update depends
on the Interval information contained in each value list. This is used in the Threshold configuration
to dispatch notifications about missing values, see collectd-threshold(5) for details.

ReadThreads Num
Number of threads to start for reading plugins. The default value is 5, but you may want to increase
this if you have more than five plugins that take a long time to read. Mostly those are plugins that
do network-IO. Setting this to a value higher than the number of registered read callbacks is not
recommended.

WriteThreads Num
Number of threads to start for dispatching value lists to write plugins. The default value is 5, but
you may want to increase this if you have more than five plugins that may take relatively long to
write to.

WriteQueueLimitHigh HighNum
WriteQueueLimitLow LowNum
Metrics are read by the read threads and then put into a queue to be handled by the write threads. If
one of the write plugins is slow (e.g. network timeouts, I/O saturation of the disk) this queue will
grow. In order to avoid running into memory issues in such a case, you can limit the size of this
queue.

By default, there is no limit and memory may grow indefinitely. This is most likely not an issue for
clients, i.e. instances that only handle the local metrics. For servers it is recommended to set this
to a non-zero value, though.

You can set the limits using WriteQueueLimitHigh and WriteQueueLimitLow. Each of them takes a
numerical argument which is the number of metrics in the queue. If there are HighNum metrics in the
queue, any new metrics will be dropped. If there are less than LowNum metrics in the queue, all new
metrics will be enqueued. If the number of metrics currently in the queue is between LowNum and
HighNum, the metric is dropped with a probability that is proportional to the number of metrics in
the queue (i.e. it increases linearly until it reaches 100%.)

If WriteQueueLimitHigh is set to non-zero and WriteQueueLimitLow is unset, the latter will default to
half of WriteQueueLimitHigh.

If you do not want to randomly drop values when the queue size is between LowNum and HighNum, set
WriteQueueLimitHigh and WriteQueueLimitLow to the same value.

Enabling the CollectInternalStats option is of great help to figure out the values to set
WriteQueueLimitHigh and WriteQueueLimitLow to.

Hostname Name
Sets the hostname that identifies a host. If you omit this setting, the hostname will be determined
using the gethostname(2) system call.

FQDNLookup true|false
If Hostname is determined automatically this setting controls whether or not the daemon should try to
figure out the "fully qualified domain name", FQDN. This is done using a lookup of the name returned
by "gethostname". This option is enabled by default.

PreCacheChain ChainName
PostCacheChain ChainName
Configure the name of the "pre-cache chain" and the "post-cache chain". Please see "FILTER
CONFIGURATION" below on information on chains and how these setting change the daemon's behavior.

PLUGIN OPTIONS

Some plugins may register own options. These options must be enclosed in a "Plugin"-Section. Which
options exist depends on the plugin used. Some plugins require external configuration, too. The "apache
plugin", for example, required "mod_status" to be configured in the webserver you're going to collect
data from. These plugins are listed below as well, even if they don't require any configuration within
collectd's configuration file.

A list of all plugins and a short summary for each plugin can be found in the README file shipped with
the sourcecode and hopefully binary packets as well.

Plugin "aggregation"
The Aggregation plugin makes it possible to aggregate several values into one using aggregation functions
such as sum, average, min and max. This can be put to a wide variety of uses, e.g. average and total CPU
statistics for your entire fleet.

The grouping is powerful but, as with many powerful tools, may be a bit difficult to wrap your head
around. The grouping will therefore be demonstrated using an example: The average and sum of the CPU
usage across all CPUs of each host is to be calculated.

To select all the affected values for our example, set "Plugin cpu" and "Type cpu". The other values are
left unspecified, meaning "all values". The Host, Plugin, PluginInstance, Type and TypeInstance options
work as if they were specified in the "WHERE" clause of an "SELECT" SQL statement.

Plugin "cpu"
Type "cpu"

Although the Host, PluginInstance (CPU number, i.e. 0, 1, 2, ...) and TypeInstance (idle, user, system,
...) fields are left unspecified in the example, the intention is to have a new value for each host /
type instance pair. This is achieved by "grouping" the values using the "GroupBy" option. It can be
specified multiple times to group by more than one field.

GroupBy "Host"
GroupBy "TypeInstance"

We do neither specify nor group by plugin instance (the CPU number), so all metrics that differ in the
CPU number only will be aggregated. Each aggregation needs at least one such field, otherwise no
aggregation would take place.

The full example configuration looks like this:

<Plugin "aggregation">
<Aggregation>
Plugin "cpu"
Type "cpu"

GroupBy "Host"
GroupBy "TypeInstance"

CalculateSum true
CalculateAverage true
</Aggregation>
</Plugin>

There are a couple of limitations you should be aware of:

• The Type cannot be left unspecified, because it is not reasonable to add apples to oranges. Also, the
internal lookup structure won't work if you try to group by type.

• There must be at least one unspecified, ungrouped field. Otherwise nothing will be aggregated.

As you can see in the example above, each aggregation has its own Aggregation block. You can have
multiple aggregation blocks and aggregation blocks may match the same values, i.e. one value list can
update multiple aggregations. The following options are valid inside Aggregation blocks:

Host Host
Plugin Plugin
PluginInstance PluginInstance
Type Type
TypeInstance TypeInstance
Selects the value lists to be added to this aggregation. Type must be a valid data set name, see
types.db(5) for details.

If the string starts with and ends with a slash ("/"), the string is interpreted as a regular
expression. The regex flavor used are POSIX extended regular expressions as described in regex(7).
Example usage:

Host "/^db[0-9]\\.example\\.com$/"

GroupBy Host|Plugin|PluginInstance|TypeInstance
Group valued by the specified field. The GroupBy option may be repeated to group by multiple fields.

SetHost Host
SetPlugin Plugin
SetPluginInstance PluginInstance
SetTypeInstance TypeInstance
Sets the appropriate part of the identifier to the provided string.

The PluginInstance should include the placeholder "%{aggregation}" which will be replaced with the
aggregation function, e.g. "average". Not including the placeholder will result in duplication
warnings and/or messed up values if more than one aggregation function are enabled.

The following example calculates the average usage of all "even" CPUs:

<Plugin "aggregation">
<Aggregation>
Plugin "cpu"
PluginInstance "/[0,2,4,6,8]$/"
Type "cpu"

SetPlugin "cpu"
SetPluginInstance "even-%{aggregation}"

GroupBy "Host"
GroupBy "TypeInstance"

CalculateAverage true
</Aggregation>
</Plugin>

This will create the files:

• foo.example.com/cpu-even-average/cpu-idle

• foo.example.com/cpu-even-average/cpu-system

• foo.example.com/cpu-even-average/cpu-user

• ...

CalculateNum true|false
CalculateSum true|false
CalculateAverage true|false
CalculateMinimum true|false
CalculateMaximum true|false
CalculateStddev true|false
Boolean options for enabling calculation of the number of value lists, their sum, average, minimum,
maximum and / or standard deviation. All options are disabled by default.

Plugin "amqp"
The AMQP plugin can be used to communicate with other instances of collectd or third party applications
using an AMQP message broker. Values are sent to or received from the broker, which handles routing,
queueing and possibly filtering or messages.

<Plugin "amqp">
# Send values to an AMQP broker
<Publish "some_name">
Host "localhost"
Port "5672"
VHost "/"
User "guest"
Password "guest"
Exchange "amq.fanout"
# ExchangeType "fanout"
# RoutingKey "collectd"
# Persistent false
# ConnectionRetryDelay 0
# Format "command"
# StoreRates false
# GraphitePrefix "collectd."
# GraphiteEscapeChar "_"
# GraphiteSeparateInstances false
# GraphiteAlwaysAppendDS false
</Publish>

# Receive values from an AMQP broker
<Subscribe "some_name">
Host "localhost"
Port "5672"
VHost "/"
User "guest"
Password "guest"
Exchange "amq.fanout"
# ExchangeType "fanout"
# Queue "queue_name"
# QueueDurable false
# QueueAutoDelete true
# RoutingKey "collectd.#"
# ConnectionRetryDelay 0
</Subscribe>
</Plugin>

The plugin's configuration consists of a number of Publish and Subscribe blocks, which configure sending
and receiving of values respectively. The two blocks are very similar, so unless otherwise noted, an
option can be used in either block. The name given in the blocks starting tag is only used for reporting
messages, but may be used to support flushing of certain Publish blocks in the future.

Host Host
Hostname or IP-address of the AMQP broker. Defaults to the default behavior of the underlying
communications library, rabbitmq-c, which is "localhost".

Port Port
Service name or port number on which the AMQP broker accepts connections. This argument must be a
string, even if the numeric form is used. Defaults to "5672".

VHost VHost
Name of the virtual host on the AMQP broker to use. Defaults to "/".

User User
Password Password
Credentials used to authenticate to the AMQP broker. By default "guest"/"guest" is used.

Exchange Exchange
In Publish blocks, this option specifies the exchange to send values to. By default, "amq.fanout"
will be used.

In Subscribe blocks this option is optional. If given, a binding between the given exchange and the
queue is created, using the routing key if configured. See the Queue and RoutingKey options below.

ExchangeType Type
If given, the plugin will try to create the configured exchange with this type after connecting. When
in a Subscribe block, the queue will then be bound to this exchange.

Queue Queue (Subscribe only)
Configures the queue name to subscribe to. If no queue name was configured explicitly, a unique queue
name will be created by the broker.

QueueDurable true|false (Subscribe only)
Defines if the queue subscribed to is durable (saved to persistent storage) or transient (will
disappear if the AMQP broker is restarted). Defaults to "false".

This option should be used in conjunction with the Persistent option on the publish side.

QueueAutoDelete true|false (Subscribe only)
Defines if the queue subscribed to will be deleted once the last consumer unsubscribes. Defaults to
"true".

RoutingKey Key
In Publish blocks, this configures the routing key to set on all outgoing messages. If not given, the
routing key will be computed from the identifier of the value. The host, plugin, type and the two
instances are concatenated together using dots as the separator and all containing dots replaced with
slashes. For example "collectd.host/example/com.cpu.0.cpu.user". This makes it possible to receive
only specific values using a "topic" exchange.

In Subscribe blocks, configures the routing key used when creating a binding between an exchange and
the queue. The usual wildcards can be used to filter messages when using a "topic" exchange. If
you're only interested in CPU statistics, you could use the routing key "collectd.*.cpu.#" for
example.

Persistent true|false (Publish only)
Selects the delivery method to use. If set to true, the persistent mode will be used, i.e. delivery
is guaranteed. If set to false (the default), the transient delivery mode will be used, i.e. messages
may be lost due to high load, overflowing queues or similar issues.

ConnectionRetryDelay Delay
When the connection to the AMQP broker is lost, defines the time in seconds to wait before attempting
to reconnect. Defaults to 0, which implies collectd will attempt to reconnect at each read interval
(in Subscribe mode) or each time values are ready for submission (in Publish mode).

Format Command|JSON|Graphite (Publish only)
Selects the format in which messages are sent to the broker. If set to Command (the default), values
are sent as "PUTVAL" commands which are identical to the syntax used by the Exec and UnixSock
plugins. In this case, the "Content-Type" header field will be set to "text/collectd".

If set to JSON, the values are encoded in the JavaScript Object Notation, an easy and straight
forward exchange format. The "Content-Type" header field will be set to "application/json".

If set to Graphite, values are encoded in the Graphite format, which is "<metric> <value>
<timestamp>\n". The "Content-Type" header field will be set to "text/graphite".

A subscribing client should use the "Content-Type" header field to determine how to decode the
values. Currently, the AMQP plugin itself can only decode the Command format.

StoreRates true|false (Publish only)
Determines whether or not "COUNTER", "DERIVE" and "ABSOLUTE" data sources are converted to a rate
(i.e. a "GAUGE" value). If set to false (the default), no conversion is performed. Otherwise the
conversion is performed using the internal value cache.

Please note that currently this option is only used if the Format option has been set to JSON.

GraphitePrefix (Publish and Format=Graphite only)
A prefix can be added in the metric name when outputting in the Graphite format. It's added before
the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphitePostfix (Publish and Format=Graphite only)
A postfix can be added in the metric name when outputting in the Graphite format. It's added after
the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphiteEscapeChar (Publish and Format=Graphite only)
Specify a character to replace dots (.) in the host part of the metric name. In Graphite metric
name, dots are used as separators between different metric parts (host, plugin, type). Default is
"_" (Underscore).

GraphiteSeparateInstances true|false
If set to true, the plugin instance and type instance will be in their own path component, for
example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and
likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle".

GraphiteAlwaysAppendDS true|false
If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false
(the default), this is only done when there is more than one DS.

Plugin "apache"
To configure the "apache"-plugin you first need to configure the Apache webserver correctly. The Apache-
plugin "mod_status" needs to be loaded and working and the "ExtendedStatus" directive needs to be
enabled. You can use the following snipped to base your Apache config upon:

ExtendedStatus on
<IfModule mod_status.c>
<Location /mod_status>
SetHandler server-status
</Location>
</IfModule>

Since its "mod_status" module is very similar to Apache's, lighttpd is also supported. It introduces a
new field, called "BusyServers", to count the number of currently connected clients. This field is also
supported.

The configuration of the Apache plugin consists of one or more "<Instance />" blocks. Each block requires
one string argument as the instance name. For example:

<Plugin "apache">
<Instance "www1">
URL "http://www1.example.com/mod_status?auto"
</Instance>
<Instance "www2">
URL "http://www2.example.com/mod_status?auto"
</Instance>
</Plugin>

The instance name will be used as the plugin instance. To emulate the old (version 4) behavior, you can
use an empty string (""). In order for the plugin to work correctly, each instance name must be unique.
This is not enforced by the plugin and it is your responsibility to ensure it.

The following options are accepted within each Instance block:

URL http://host/mod_status?auto
Sets the URL of the "mod_status" output. This needs to be the output generated by "ExtendedStatus on"
and it needs to be the machine readable output generated by appending the "?auto" argument. This
option is mandatory.

User Username
Optional user name needed for authentication.

Password Password
Optional password needed for authentication.

VerifyPeer true|false
Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for
details. Enabled by default.

VerifyHost true|false
Enable or disable peer host name verification. If enabled, the plugin checks if the "Common Name" or
a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL
option. If this identity check fails, the connection is aborted. Obviously, only works when
connecting to a SSL enabled server. Enabled by default.

CACert File
File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this
option. What CA certificates come bundled with "libcurl" and are checked by default depends on the
distribution you use.

SSLCiphers list of ciphers
Specifies which ciphers to use in the connection. The list of ciphers must specify valid ciphers. See
<http://www.openssl.org/docs/apps/ciphers.html> for details.

Timeout Milliseconds
The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default,
the configured Interval is used to set the timeout.

Plugin "apcups"
Host Hostname
Hostname of the host running apcupsd. Defaults to localhost. Please note that IPv6 support has been
disabled unless someone can confirm or decline that apcupsd can handle it.

Port Port
TCP-Port to connect to. Defaults to 3551.

ReportSeconds true|false
If set to true, the time reported in the "timeleft" metric will be converted to seconds. This is the
recommended setting. If set to false, the default for backwards compatibility, the time will be
reported in minutes.

Plugin "aquaero"
This plugin collects the value of the available sensors in an Aquaero 5 board. Aquaero 5 is a water-
cooling controller board, manufactured by Aqua Computer GmbH <http://www.aquacomputer.de/>, with a USB2
connection for monitoring and configuration. The board can handle multiple temperature sensors, fans,
water pumps and water level sensors and adjust the output settings such as fan voltage or power used by
the water pump based on the available inputs using a configurable controller included in the board. This
plugin collects all the available inputs as well as some of the output values chosen by this controller.
The plugin is based on the libaquaero5 library provided by aquatools-ng.

Device DevicePath
Device path of the Aquaero 5's USB HID (human interface device), usually in the form
"/dev/usb/hiddevX". If this option is no set the plugin will try to auto-detect the Aquaero 5 USB
device based on vendor-ID and product-ID.

Plugin "ascent"
This plugin collects information about an Ascent server, a free server for the "World of Warcraft" game.
This plugin gathers the information by fetching the XML status page using "libcurl" and parses it using
"libxml2".

The configuration options are the same as for the "apache" plugin above:

URL http://localhost/ascent/status/
Sets the URL of the XML status output.

User Username
Optional user name needed for authentication.

Password Password
Optional password needed for authentication.

VerifyPeer true|false
Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for
details. Enabled by default.

Timeout Milliseconds
The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default,
the configured Interval is used to set the timeout.

Plugin "barometer"
This plugin reads absolute air pressure using digital barometer sensor on a I2C bus. Supported sensors
are:

MPL115A2 from Freescale, see <http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL115A>.
MPL3115 from Freescale see <http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPL3115A2>.
BMP085 from Bosch Sensortec

The sensor type - one of the above - is detected automatically by the plugin and indicated in the
plugin_instance (you will see subdirectory "barometer-mpl115" or "barometer-mpl3115", or
"barometer-bmp085"). The order of detection is BMP085 -> MPL3115 -> MPL115A2, the first one found will be
used (only one sensor can be used by the plugin).

The plugin provides absolute barometric pressure, air pressure reduced to sea level (several possible
approximations) and as an auxiliary value also internal sensor temperature. It uses (expects/provides)
typical metric units - pressure in [hPa], temperature in [C], altitude in [m].

It was developed and tested under Linux only. The only platform dependency is the standard Linux i2c-dev
interface (the particular bus driver has to support the SM Bus command subset).

The reduction or normalization to mean sea level pressure requires (depending on selected
method/approximation) also altitude and reference to temperature sensor(s). When multiple temperature
sensors are configured the minumum of their values is always used (expecting that the warmer ones are
affected by e.g. direct sun light at that moment).

Synopsis:

<Plugin "barometer">
Device "/dev/i2c-0";
Oversampling 512
PressureOffset 0.0
TemperatureOffset 0.0
Normalization 2
Altitude 238.0
TemperatureSensor "myserver/onewire-F10FCA000800/temperature"
</Plugin>

Device device
The only mandatory configuration parameter.

Device name of the I2C bus to which the sensor is connected. Note that typically you need to have
loaded the i2c-dev module. Using i2c-tools you can check/list i2c buses available on your system by:

i2cdetect -l

Then you can scan for devices on given bus. E.g. to scan the whole bus 0 use:

i2cdetect -y -a 0

This way you should be able to verify that the pressure sensor (either type) is connected and
detected on address 0x60.

Oversampling value
Optional parameter controlling the oversampling/accuracy. Default value is 1 providing fastest and
least accurate reading.

For MPL115 this is the size of the averaging window. To filter out sensor noise a simple averaging
using floating window of this configurable size is used. The plugin will use average of the last
"value" measurements (value of 1 means no averaging). Minimal size is 1, maximal 1024.

For MPL3115 this is the oversampling value. The actual oversampling is performed by the sensor and
the higher value the higher accuracy and longer conversion time (although nothing to worry about in
the collectd context). Supported values are: 1, 2, 4, 8, 16, 32, 64 and 128. Any other value is
adjusted by the plugin to the closest supported one.

For BMP085 this is the oversampling value. The actual oversampling is performed by the sensor and the
higher value the higher accuracy and longer conversion time (although nothing to worry about in the
collectd context). Supported values are: 1, 2, 4, 8. Any other value is adjusted by the plugin to
the closest supported one.

PressureOffset offset
Optional parameter for MPL3115 only.

You can further calibrate the sensor by supplying pressure and/or temperature offsets. This is added
to the measured/caclulated value (i.e. if the measured value is too high then use negative offset).
In hPa, default is 0.0.

TemperatureOffset offset
Optional parameter for MPL3115 only.

Normalization method
Optional parameter, default value is 0.

Normalization method - what approximation/model is used to compute the mean sea level pressure from
the air absolute pressure.

Supported values of the "method" (integer between from 0 to 2) are:

0 - no conversion, absolute pressure is simply copied over. For this method you do not need to
configure "Altitude" or "TemperatureSensor".
1 - international formula for conversion , See
<http://en.wikipedia.org/wiki/Atmospheric_pressure#Altitude_atmospheric_pressure_variation>. For this
method you have to configure "Altitude" but do not need "TemperatureSensor" (uses fixed global
temperature average instead).
2 - formula as recommended by the Deutsche Wetterdienst (German Meteorological Service). See
<http://de.wikipedia.org/wiki/Barometrische_H%C3%B6henformel#Theorie> For this method you have to
configure both "Altitude" and "TemperatureSensor".
Altitude altitude
The altitude (in meters) of the location where you meassure the pressure.

TemperatureSensor reference
Temperature sensor(s) which should be used as a reference when normalizing the pressure using
"Normalization" method 2. When specified more sensors a minumum is found and used each time. The
temperature reading directly from this pressure sensor/plugin is typically not suitable as the
pressure sensor will be probably inside while we want outside temperature. The collectd reference
name is something like <hostname>/<plugin_name>-<plugin_instance>/<type>-<type_instance>
(<type_instance> is usually omitted when there is just single value type). Or you can figure it out
from the path of the output data files.

Plugin "battery"
The battery plugin reports the remaining capacity, power and voltage of laptop batteries.

ValuesPercentage false|true
When enabled, remaining capacity is reported as a percentage, e.g. "42% capacity remaining".
Otherwise the capacity is stored as reported by the battery, most likely in "Wh". This option does
not work with all input methods, in particular when only "/proc/pmu" is available on an old Linux
system. Defaults to false.

ReportDegraded false|true
Typical laptop batteries degrade over time, meaning the capacity decreases with recharge cycles. The
maximum charge of the previous charge cycle is tracked as "last full capacity" and used to determine
that a battery is "fully charged".

When this option is set to false, the default, the battery plugin will only report the remaining
capacity. If the ValuesPercentage option is enabled, the relative remaining capacity is calculated as
the ratio of the "remaining capacity" and the "last full capacity". This is what most tools, such as
the status bar of desktop environments, also do.

When set to true, the battery plugin will report three values: charged (remaining capacity),
discharged (difference between "last full capacity" and "remaining capacity") and degraded
(difference between "design capacity" and "last full capacity").

Plugin "bind"
Starting with BIND 9.5.0, the most widely used DNS server software provides extensive statistics about
queries, responses and lots of other information. The bind plugin retrieves this information that's
encoded in XML and provided via HTTP and submits the values to collectd.

To use this plugin, you first need to tell BIND to make this information available. This is done with the
"statistics-channels" configuration option:

statistics-channels {
inet localhost port 8053;
};

The configuration follows the grouping that can be seen when looking at the data with an XSLT compatible
viewer, such as a modern web browser. It's probably a good idea to make yourself familiar with the
provided values, so you can understand what the collected statistics actually mean.

Synopsis:

<Plugin "bind">
URL "http://localhost:8053/"
ParseTime false
OpCodes true
QTypes true

ServerStats true
ZoneMaintStats true
ResolverStats false
MemoryStats true

<View "_default">
QTypes true
ResolverStats true
CacheRRSets true

Zone "127.in-addr.arpa/IN"
</View>
</Plugin>

The bind plugin accepts the following configuration options:

URL URL
URL from which to retrieve the XML data. If not specified, "http://localhost:8053/" will be used.

ParseTime true|false
When set to true, the time provided by BIND will be parsed and used to dispatch the values. When set
to false, the local time source is queried.

This setting is set to true by default for backwards compatibility; setting this to false is
recommended to avoid problems with timezones and localization.

OpCodes true|false
When enabled, statistics about the "OpCodes", for example the number of "QUERY" packets, are
collected.

Default: Enabled.

QTypes true|false
When enabled, the number of incoming queries by query types (for example "A", "MX", "AAAA") is
collected.

Default: Enabled.

ServerStats true|false
Collect global server statistics, such as requests received over IPv4 and IPv6, successful queries,
and failed updates.

Default: Enabled.

ZoneMaintStats true|false
Collect zone maintenance statistics, mostly information about notifications (zone updates) and zone
transfers.

Default: Enabled.

ResolverStats true|false
Collect resolver statistics, i. e. statistics about outgoing requests (e. g. queries over IPv4, lame
servers). Since the global resolver counters apparently were removed in BIND 9.5.1 and 9.6.0, this is
disabled by default. Use the ResolverStats option within a View "_default" block instead for the same
functionality.

Default: Disabled.

MemoryStats
Collect global memory statistics.

Default: Enabled.

Timeout Milliseconds
The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default,
the configured Interval is used to set the timeout.

View Name
Collect statistics about a specific "view". BIND can behave different, mostly depending on the source
IP-address of the request. These different configurations are called "views". If you don't use this
feature, you most likely are only interested in the "_default" view.

Within a <View name> block, you can specify which information you want to collect about a view. If no
View block is configured, no detailed view statistics will be collected.

QTypes true|false
If enabled, the number of outgoing queries by query type (e. g. "A", "MX") is collected.

Default: Enabled.

ResolverStats true|false
Collect resolver statistics, i. e. statistics about outgoing requests (e. g. queries over IPv4,
lame servers).

Default: Enabled.

CacheRRSets true|false
If enabled, the number of entries ("RR sets") in the view's cache by query type is collected.
Negative entries (queries which resulted in an error, for example names that do not exist) are
reported with a leading exclamation mark, e. g. "!A".

Default: Enabled.

Zone Name
When given, collect detailed information about the given zone in the view. The information
collected if very similar to the global ServerStats information (see above).

You can repeat this option to collect detailed information about multiple zones.

By default no detailed zone information is collected.

Plugin "ceph"
The ceph plugin collects values from JSON data to be parsed by libyajl (<https://lloyd.github.io/yajl/>)
retrieved from ceph daemon admin sockets.

A separate Daemon block must be configured for each ceph daemon to be monitored. The following example
will read daemon statistics from four separate ceph daemons running on the same device (two OSDs, one
MON, one MDS) :

<Plugin ceph>
LongRunAvgLatency false
ConvertSpecialMetricTypes true
<Daemon "osd.0">
SocketPath "/var/run/ceph/ceph-osd.0.asok"
</Daemon>
<Daemon "osd.1">
SocketPath "/var/run/ceph/ceph-osd.1.asok"
</Daemon>
<Daemon "mon.a">
SocketPath "/var/run/ceph/ceph-mon.ceph1.asok"
</Daemon>
<Daemon "mds.a">
SocketPath "/var/run/ceph/ceph-mds.ceph1.asok"
</Daemon>
</Plugin>

The ceph plugin accepts the following configuration options:

LongRunAvgLatency true|false
If enabled, latency values(sum,count pairs) are calculated as the long run average - average since
the ceph daemon was started = (sum / count). When disabled, latency values are calculated as the
average since the last collection = (sum_now - sum_last) / (count_now - count_last).

Default: Disabled

ConvertSpecialMetricTypes true|false
If enabled, special metrics (metrics that differ in type from similar counters) are converted to the
type of those similar counters. This currently only applies to filestore.journal_wr_bytes which is a
counter for OSD daemons. The ceph schema reports this metric type as a sum,count pair while similar
counters are treated as derive types. When converted, the sum is used as the counter value and is
treated as a derive type. When disabled, all metrics are treated as the types received from the ceph
schema.

Default: Enabled

Each Daemon block must have a string argument for the plugin instance name. A SocketPath is also
required for each Daemon block:

Daemon DaemonName
Name to be used as the instance name for this daemon.

SocketPath SocketPath
Specifies the path to the UNIX admin socket of the ceph daemon.

Plugin "cgroups"
This plugin collects the CPU user/system time for each cgroup by reading the cpuacct.stat files in the
first cpuacct-mountpoint (typically /sys/fs/cgroup/cpu.cpuacct on machines using systemd).

CGroup Directory
Select cgroup based on the name. Whether only matching cgroups are collected or if they are ignored
is controlled by the IgnoreSelected option; see below.

IgnoreSelected true|false
Invert the selection: If set to true, all cgroups except the ones that match any one of the criteria
are collected. By default only selected cgroups are collected if a selection is made. If no selection
is configured at all, all cgroups are selected.

Plugin "conntrack"
This plugin collects IP conntrack statistics.

OldFiles
Assume the conntrack_count and conntrack_max files to be found in /proc/sys/net/ipv4/netfilter
instead of /proc/sys/net/netfilter/.

Plugin "cpu"
The CPU plugin collects CPU usage metrics. By default, CPU usage is reported as Jiffies, using the "cpu"
type. Two aggregations are available:

• Sum, per-state, over all CPUs installed in the system; and

• Sum, per-CPU, over all non-idle states of a CPU, creating an "active" state.

The two aggregations can be combined, leading to collectd only emitting a single "active" metric for the
entire system. As soon as one of these aggregations (or both) is enabled, the cpu plugin will report a
percentage, rather than Jiffies. In addition, you can request individual, per-state, per-CPU metrics to
be reported as percentage.

The following configuration options are available:

ReportByState true|false
When set to true, the default, reports per-state metrics, e.g. "system", "user" and "idle". When set
to false, aggregates (sums) all non-idle states into one "active" metric.

ReportByCpu true|false
When set to true, the default, reports per-CPU (per-core) metrics. When set to false, instead of
reporting metrics for individual CPUs, only a global sum of CPU states is emitted.

ValuesPercentage false|true
This option is only considered when both, ReportByCpu and ReportByState are set to true. In this
case, by default, metrics will be reported as Jiffies. By setting this option to true, you can
request percentage values in the un-aggregated (per-CPU, per-state) mode as well.

Plugin "cpufreq"
This plugin doesn't have any options. It reads /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq (for
the first CPU installed) to get the current CPU frequency. If this file does not exist make sure cpufreqd
(<http://cpufreqd.sourceforge.net/>) or a similar tool is installed and an "cpu governor" (that's a
kernel module) is loaded.

Plugin "csv"
DataDir Directory
Set the directory to store CSV-files under. Per default CSV-files are generated beneath the daemon's
working directory, i. e. the BaseDir. The special strings stdout and stderr can be used to write to
the standard output and standard error channels, respectively. This, of course, only makes much sense
when collectd is running in foreground- or non-daemon-mode.

StoreRates true|false
If set to true, convert counter values to rates. If set to false (the default) counter values are
stored as is, i. e. as an increasing integer number.

Plugin "curl"
The curl plugin uses the libcurl (<http://curl.haxx.se/>) to read web pages and the match infrastructure
(the same code used by the tail plugin) to use regular expressions with the received data.

The following example will read the current value of AMD stock from Google's finance page and dispatch
the value to collectd.

<Plugin curl>
<Page "stock_quotes">
URL "http://finance.google.com/finance?q=NYSE%3AAMD"
User "foo"
Password "bar"
Digest false
VerifyPeer true
VerifyHost true
CACert "/path/to/ca.crt"
Header "X-Custom-Header: foobar"
Post "foo=bar"

MeasureResponseTime false
MeasureResponseCode false

<Match>
Regex "<span +class=\"pr\"[^>]*> *([0-9]*\\.[0-9]+) *</span>"
DSType "GaugeAverage"
# Note: `stock_value' is not a standard type.
Type "stock_value"
Instance "AMD"
</Match>
</Page>
</Plugin>

In the Plugin block, there may be one or more Page blocks, each defining a web page and one or more
"matches" to be performed on the returned data. The string argument to the Page block is used as plugin
instance.

The following options are valid within Page blocks:

URL URL
URL of the web site to retrieve. Since a regular expression will be used to extract information from
this data, non-binary data is a big plus here ;)

User Name
Username to use if authorization is required to read the page.

Password Password
Password to use if authorization is required to read the page.

Digest true|false
Enable HTTP digest authentication.

VerifyPeer true|false
Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for
details. Enabled by default.

CACert file
File that holds one or more SSL certificates. If you want to use HTTPS you will possibly need this
option. What CA certificates come bundled with "libcurl" and are checked by default depends on the
distribution you use.

Header Header
A HTTP header to add to the request. Multiple headers are added if this option is specified more than
once.

Post Body
Specifies that the HTTP operation should be a POST instead of a GET. The complete data to be posted
is given as the argument. This option will usually need to be accompanied by a Header option to set
an appropriate "Content-Type" for the post body (e.g. to "application/x-www-form-urlencoded").

MeasureResponseTime true|false
Measure response time for the request. If this setting is enabled, Match blocks (see below) are
optional. Disabled by default.

Beware that requests will get aborted if they take too long to complete. Adjust Timeout accordingly
if you expect MeasureResponseTime to report such slow requests.

MeasureResponseCode true|false
Measure response code for the request. If this setting is enabled, Match blocks (see below) are
optional. Disabled by default.

<Match>
One or more Match blocks that define how to match information in the data returned by "libcurl". The
"curl" plugin uses the same infrastructure that's used by the "tail" plugin, so please see the
documentation of the "tail" plugin below on how matches are defined. If the MeasureResponseTime or
MeasureResponseCode options are set to true, Match blocks are optional.

Timeout Milliseconds
The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default,
the configured Interval is used to set the timeout. Prior to version 5.5.0, there was no timeout and
requests could hang indefinitely. This legacy behaviour can be achieved by setting the value of
Timeout to 0.

If Timeout is 0 or bigger than the Interval, keep in mind that each slow network connection will
stall one read thread. Adjust the ReadThreads global setting accordingly to prevent this from
blocking other plugins.

Plugin "curl_json"
The curl_json plugin collects values from JSON data to be parsed by libyajl
(<https://lloyd.github.io/yajl/>) retrieved via either libcurl (<http://curl.haxx.se/>) or read directly
from a unix socket. The former can be used, for example, to collect values from CouchDB documents (which
are stored JSON notation), and the latter to collect values from a uWSGI stats socket.

The following example will collect several values from the built-in "_stats" runtime statistics module of
CouchDB (<http://wiki.apache.org/couchdb/Runtime_Statistics>).

<Plugin curl_json>
<URL "http://localhost:5984/_stats">
Instance "httpd"
<Key "httpd/requests/count">
Type "http_requests"
</Key>

<Key "httpd_request_methods/*/count">
Type "http_request_methods"
</Key>

<Key "httpd_status_codes/*/count">
Type "http_response_codes"
</Key>
</URL>
</Plugin>

This example will collect data directly from a uWSGI "Stats Server" socket.

<Plugin curl_json>
<Sock "/var/run/uwsgi.stats.sock">
Instance "uwsgi"
<Key "workers/*/requests">
Type "http_requests"
</Key>

<Key "workers/*/apps/*/requests">
Type "http_requests"
</Key>
</Sock>
</Plugin>

In the Plugin block, there may be one or more URL blocks, each defining a URL to be fetched via HTTP
(using libcurl) or Sock blocks defining a unix socket to read JSON from directly. Each of these blocks
may have one or more Key blocks.

The Key string argument must be in a path format. Each component is used to match the key from a JSON map
or the index of an JSON array. If a path component of a Key is a * wildcard, the values for all map keys
or array indices will be collectd.

The following options are valid within URL blocks:

Instance Instance
Sets the plugin instance to Instance.

Interval Interval
Sets the interval (in seconds) in which the values will be collected from this URL. By default the
global Interval setting will be used.

User Name
Password Password
Digest true|false
VerifyPeer true|false
VerifyHost true|false
CACert file
Header Header
Post Body
Timeout Milliseconds
These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see
there for a detailed description.

The following options are valid within Key blocks:

Type Type
Sets the type used to dispatch the values to the daemon. Detailed information about types and their
configuration can be found in types.db(5). This option is mandatory.

Instance Instance
Type-instance to use. Defaults to the current map key or current string array element value.

Plugin "curl_xml"
The curl_xml plugin uses libcurl (<http://curl.haxx.se/>) and libxml2 (<http://xmlsoft.org/>) to retrieve
XML data via cURL.

<Plugin "curl_xml">
<URL "http://localhost/stats.xml">
Host "my_host"
Instance "some_instance"
User "collectd"
Password "thaiNg0I"
VerifyPeer true
VerifyHost true
CACert "/path/to/ca.crt"
Header "X-Custom-Header: foobar"
Post "foo=bar"

<XPath "table[@id=\"magic_level\"]/tr">
Type "magic_level"
#InstancePrefix "prefix-"
InstanceFrom "td[1]"
ValuesFrom "td[2]/span[@class=\"level\"]"
</XPath>
</URL>
</Plugin>

In the Plugin block, there may be one or more URL blocks, each defining a URL to be fetched using
libcurl. Within each URL block there are options which specify the connection parameters, for example
authentication information, and one or more XPath blocks.

Each XPath block specifies how to get one type of information. The string argument must be a valid XPath
expression which returns a list of "base elements". One value is dispatched for each "base element". The
type instance and values are looked up using further XPath expressions that should be relative to the
base element.

Within the URL block the following options are accepted:

Host Name
Use Name as the host name when submitting values. Defaults to the global host name setting.

Instance Instance
Use Instance as the plugin instance when submitting values. Defaults to an empty string (no plugin
instance).

Namespace Prefix URL
If an XPath expression references namespaces, they must be specified with this option. Prefix is the
"namespace prefix" used in the XML document. URL is the "namespace name", an URI reference uniquely
identifying the namespace. The option can be repeated to register multiple namespaces.

Examples:

Namespace "s" "http://schemas.xmlsoap.org/soap/envelope/"
Namespace "m" "http://www.w3.org/1998/Math/MathML"

User User
Password Password
Digest true|false
VerifyPeer true|false
VerifyHost true|false
CACert CA Cert File
Header Header
Post Body
Timeout Milliseconds
These options behave exactly equivalent to the appropriate options of the cURL plugin. Please see
there for a detailed description.

<XPath XPath-expression>
Within each URL block, there must be one or more XPath blocks. Each XPath block specifies how to get
one type of information. The string argument must be a valid XPath expression which returns a list of
"base elements". One value is dispatched for each "base element".

Within the XPath block the following options are accepted:

Type Type
Specifies the Type used for submitting patches. This determines the number of values that are
required / expected and whether the strings are parsed as signed or unsigned integer or as double
values. See types.db(5) for details. This option is required.

InstancePrefix InstancePrefix
Prefix the type instance with InstancePrefix. The values are simply concatenated together without
any separator. This option is optional.

InstanceFrom InstanceFrom
Specifies a XPath expression to use for determining the type instance. The XPath expression must
return exactly one element. The element's value is then used as type instance, possibly prefixed
with InstancePrefix (see above).

This value is required. As a special exception, if the "base XPath expression" (the argument to
the XPath block) returns exactly one argument, then this option may be omitted.

ValuesFrom ValuesFrom [ValuesFrom ...]
Specifies one or more XPath expression to use for reading the values. The number of XPath
expressions must match the number of data sources in the type specified with Type (see above).
Each XPath expression must return exactly one element. The element's value is then parsed as a
number and used as value for the appropriate value in the value list dispatched to the daemon.

Plugin "dbi"
This plugin uses the dbi library (<http://libdbi.sourceforge.net/>) to connect to various databases,
execute SQL statements and read back the results. dbi is an acronym for "database interface" in case you
were wondering about the name. You can configure how each column is to be interpreted and the plugin will
generate one or more data sets from each row returned according to these rules.

Because the plugin is very generic, the configuration is a little more complex than those of other
plugins. It usually looks something like this:

<Plugin dbi>
<Query "out_of_stock">
Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
# Use with MySQL 5.0.0 or later
MinVersion 50000
<Result>
Type "gauge"
InstancePrefix "out_of_stock"
InstancesFrom "category"
ValuesFrom "value"
</Result>
</Query>
<Database "product_information">
Driver "mysql"
DriverOption "host" "localhost"
DriverOption "username" "collectd"
DriverOption "password" "aZo6daiw"
DriverOption "dbname" "prod_info"
SelectDB "prod_info"
Query "out_of_stock"
</Database>
</Plugin>

The configuration above defines one query with one result and one database. The query is then linked to
the database with the Query option within the <Database> block. You can have any number of queries and
databases and you can also use the Include statement to split up the configuration file in multiple,
smaller files. However, the <Query> block must precede the <Database> blocks, because the file is
interpreted from top to bottom!

The following is a complete list of options:

Query blocks

Query blocks define SQL statements and how the returned data should be interpreted. They are identified
by the name that is given in the opening line of the block. Thus the name needs to be unique. Other than
that, the name is not used in collectd.

In each Query block, there is one or more Result blocks. Result blocks define which column holds which
value or instance information. You can use multiple Result blocks to create multiple values from one
returned row. This is especially useful, when queries take a long time and sending almost the same query
again and again is not desirable.

Example:

<Query "environment">
Statement "select station, temperature, humidity from environment"
<Result>
Type "temperature"
# InstancePrefix "foo"
InstancesFrom "station"
ValuesFrom "temperature"
</Result>
<Result>
Type "humidity"
InstancesFrom "station"
ValuesFrom "humidity"
</Result>
</Query>

The following options are accepted:

Statement SQL
Sets the statement that should be executed on the server. This is not interpreted by collectd, but
simply passed to the database server. Therefore, the SQL dialect that's used depends on the server
collectd is connected to.

The query has to return at least two columns, one for the instance and one value. You cannot omit the
instance, even if the statement is guaranteed to always return exactly one line. In that case, you
can usually specify something like this:

Statement "SELECT \"instance\", COUNT(*) AS value FROM table"

(That works with MySQL but may not be valid SQL according to the spec. If you use a more strict
database server, you may have to select from a dummy table or something.)

Please note that some databases, for example Oracle, will fail if you include a semicolon at the end
of the statement.

MinVersion Version
MaxVersion Value
Only use this query for the specified database version. You can use these options to provide multiple
queries with the same name but with a slightly different syntax. The plugin will use only those
queries, where the specified minimum and maximum versions fit the version of the database in use.

The database version is determined by "dbi_conn_get_engine_version", see the libdbi documentation
<http://libdbi.sourceforge.net/docs/programmers-guide/reference-conn.html#DBI-CONN-GET-ENGINE-
VERSION> for details. Basically, each part of the version is assumed to be in the range from 00 to 99
and all dots are removed. So version "4.1.2" becomes "40102", version "5.0.42" becomes "50042".

Warning: The plugin will use all matching queries, so if you specify multiple queries with the same
name and overlapping ranges, weird stuff will happen. Don't to it! A valid example would be something
along these lines:

MinVersion 40000
MaxVersion 49999
...
MinVersion 50000
MaxVersion 50099
...
MinVersion 50100
# No maximum

In the above example, there are three ranges that don't overlap. The last one goes from version
"5.1.0" to infinity, meaning "all later versions". Versions before "4.0.0" are not specified.

Type Type
The type that's used for each line returned. See types.db(5) for more details on how types are
defined. In short: A type is a predefined layout of data and the number of values and type of values
has to match the type definition.

If you specify "temperature" here, you need exactly one gauge column. If you specify "if_octets", you
will need two counter columns. See the ValuesFrom setting below.

There must be exactly one Type option inside each Result block.

InstancePrefix prefix
Prepends prefix to the type instance. If InstancesFrom (see below) is not given, the string is simply
copied. If InstancesFrom is given, prefix and all strings returned in the appropriate columns are
concatenated together, separated by dashes ("-").

InstancesFrom column0 [column1 ...]
Specifies the columns whose values will be used to create the "type-instance" for each row. If you
specify more than one column, the value of all columns will be joined together with dashes ("-") as
separation characters.

The plugin itself does not check whether or not all built instances are different. It's your
responsibility to assure that each is unique. This is especially true, if you do not specify
InstancesFrom: You have to make sure that only one row is returned in this case.

If neither InstancePrefix nor InstancesFrom is given, the type-instance will be empty.

ValuesFrom column0 [column1 ...]
Names the columns whose content is used as the actual data for the data sets that are dispatched to
the daemon. How many such columns you need is determined by the Type setting above. If you specify
too many or not enough columns, the plugin will complain about that and no data will be submitted to
the daemon.

The actual data type in the columns is not that important. The plugin will automatically cast the
values to the right type if it know how to do that. So it should be able to handle integer an
floating point types, as well as strings (if they include a number at the beginning).

There must be at least one ValuesFrom option inside each Result block.

MetadataFrom [column0 column1 ...]
Names the columns whose content is used as metadata for the data sets that are dispatched to the
daemon.

Database blocks

Database blocks define a connection to a database and which queries should be sent to that database.
Since the used "dbi" library can handle a wide variety of databases, the configuration is very generic.
If in doubt, refer to libdbi's documentation - we stick as close to the terminology used there.

Each database needs a "name" as string argument in the starting tag of the block. This name will be used
as "PluginInstance" in the values submitted to the daemon. Other than that, that name is not used.

Driver Driver
Specifies the driver to use to connect to the database. In many cases those drivers are named after
the database they can connect to, but this is not a technical necessity. These drivers are sometimes
referred to as "DBD", DataBase Driver, and some distributions ship them in separate packages. Drivers
for the "dbi" library are developed by the libdbi-drivers project at
<http://libdbi-drivers.sourceforge.net/>.

You need to give the driver name as expected by the "dbi" library here. You should be able to find
that in the documentation for each driver. If you mistype the driver name, the plugin will dump a
list of all known driver names to the log.

DriverOption Key Value
Sets driver-specific options. What option a driver supports can be found in the documentation for
each driver, somewhere at <http://libdbi-drivers.sourceforge.net/>. However, the options "host",
"username", "password", and "dbname" seem to be de facto standards.

DBDs can register two types of options: String options and numeric options. The plugin will use the
"dbi_conn_set_option" function when the configuration provides a string and the
"dbi_conn_require_option_numeric" function when the configuration provides a number. So these two
lines will actually result in different calls being used:

DriverOption "Port" 1234 # numeric
DriverOption "Port" "1234" # string

Unfortunately, drivers are not too keen to report errors when an unknown option is passed to them, so
invalid settings here may go unnoticed. This is not the plugin's fault, it will report errors if it
gets them from the library / the driver. If a driver complains about an option, the plugin will dump
a complete list of all options understood by that driver to the log. There is no way to
programatically find out if an option expects a string or a numeric argument, so you will have to
refer to the appropriate DBD's documentation to find this out. Sorry.

SelectDB Database
In some cases, the database name you connect with is not the database name you want to use for
querying data. If this option is set, the plugin will "select" (switch to) that database after the
connection is established.

Query QueryName
Associates the query named QueryName with this database connection. The query needs to be defined
before this statement, i. e. all query blocks you want to refer to must be placed above the database
block you want to refer to them from.

Host Hostname
Sets the host field of value lists to Hostname when dispatching values. Defaults to the global
hostname setting.

Plugin "df"
Device Device
Select partitions based on the devicename.

MountPoint Directory
Select partitions based on the mountpoint.

FSType FSType
Select partitions based on the filesystem type.

IgnoreSelected true|false
Invert the selection: If set to true, all partitions except the ones that match any one of the
criteria are collected. By default only selected partitions are collected if a selection is made. If
no selection is configured at all, all partitions are selected.

ReportByDevice true|false
Report using the device name rather than the mountpoint. i.e. with this false, (the default), it will
report a disk as "root", but with it true, it will be "sda1" (or whichever).

ReportInodes true|false
Enables or disables reporting of free, reserved and used inodes. Defaults to inode collection being
disabled.

Enable this option if inodes are a scarce resource for you, usually because many small files are
stored on the disk. This is a usual scenario for mail transfer agents and web caches.

ValuesAbsolute true|false
Enables or disables reporting of free and used disk space in 1K-blocks. Defaults to true.

ValuesPercentage false|true
Enables or disables reporting of free and used disk space in percentage. Defaults to false.

This is useful for deploying collectd on the cloud, where machines with different disk size may
exist. Then it is more practical to configure thresholds based on relative disk size.

Plugin "disk"
The "disk" plugin collects information about the usage of physical disks and logical disks (partitions).
Values collected are the number of octets written to and read from a disk or partition, the number of
read/write operations issued to the disk and a rather complex "time" it took for these commands to be
issued.

Using the following two options you can ignore some disks or configure the collection only of specific
disks.

Disk Name
Select the disk Name. Whether it is collected or ignored depends on the IgnoreSelected setting, see
below. As with other plugins that use the daemon's ignorelist functionality, a string that starts and
ends with a slash is interpreted as a regular expression. Examples:

Disk "sdd"
Disk "/hda[34]/"

IgnoreSelected true|false
Sets whether selected disks, i. e. the ones matches by any of the Disk statements, are ignored or if
all other disks are ignored. The behavior (hopefully) is intuitive: If no Disk option is configured,
all disks are collected. If at least one Disk option is given and no IgnoreSelected or set to false,
only matching disks will be collected. If IgnoreSelected is set to true, all disks are collected
except the ones matched.

UseBSDName true|false
Whether to use the device's "BSD Name", on Mac OS X, instead of the default major/minor numbers.
Requires collectd to be built with Apple's IOKitLib support.

UdevNameAttr Attribute
Attempt to override disk instance name with the value of a specified udev attribute when built with
libudev. If the attribute is not defined for the given device, the default name is used. Example:

UdevNameAttr "DM_NAME"

Plugin "dns"
Interface Interface
The dns plugin uses libpcap to capture dns traffic and analyzes it. This option sets the interface
that should be used. If this option is not set, or set to "any", the plugin will try to get packets
from all interfaces. This may not work on certain platforms, such as Mac OS X.

IgnoreSource IP-address
Ignore packets that originate from this address.

SelectNumericQueryTypes true|false
Enabled by default, collects unknown (and thus presented as numeric only) query types.

Plugin "email"
SocketFile Path
Sets the socket-file which is to be created.

SocketGroup Group
If running as root change the group of the UNIX-socket after it has been created. Defaults to
collectd.

SocketPerms Permissions
Change the file permissions of the UNIX-socket after it has been created. The permissions must be
given as a numeric, octal value as you would pass to chmod(1). Defaults to 0770.

MaxConns Number
Sets the maximum number of connections that can be handled in parallel. Since this many threads will
be started immediately setting this to a very high value will waste valuable resources. Defaults to 5
and will be forced to be at most 16384 to prevent typos and dumb mistakes.

Plugin "ethstat"
The ethstat plugin collects information about network interface cards (NICs) by talking directly with the
underlying kernel driver using ioctl(2).

Synopsis:

<Plugin "ethstat">
Interface "eth0"
Map "rx_csum_offload_errors" "if_rx_errors" "checksum_offload"
Map "multicast" "if_multicast"
</Plugin>

Options:

Interface Name
Collect statistical information about interface Name.

Map Name Type [TypeInstance]
By default, the plugin will submit values as type "derive" and type instance set to Name, the name of
the metric as reported by the driver. If an appropriate Map option exists, the given Type and,
optionally, TypeInstance will be used.

MappedOnly true|false
When set to true, only metrics that can be mapped to to a type will be collected, all other metrics
will be ignored. Defaults to false.

Plugin "exec"
Please make sure to read collectd-exec(5) before using this plugin. It contains valuable information on
when the executable is executed and the output that is expected from it.

Exec User[:[Group]] Executable [<arg> [<arg> ...]]
NotificationExec User[:[Group]] Executable [<arg> [<arg> ...]]
Execute the executable Executable as user User. If the user name is followed by a colon and a group
name, the effective group is set to that group. The real group and saved-set group will be set to
the default group of that user. If no group is given the effective group ID will be the same as the
real group ID.

Please note that in order to change the user and/or group the daemon needs superuser privileges. If
the daemon is run as an unprivileged user you must specify the same user/group here. If the daemon is
run with superuser privileges, you must supply a non-root user here.

The executable may be followed by optional arguments that are passed to the program. Please note that
due to the configuration parsing numbers and boolean values may be changed. If you want to be
absolutely sure that something is passed as-is please enclose it in quotes.

The Exec and NotificationExec statements change the semantics of the programs executed, i. e. the
data passed to them and the response expected from them. This is documented in great detail in
collectd-exec(5).

Plugin "fhcount"
The "fhcount" plugin provides statistics about used, unused and total number of file handles on Linux.

The fhcount plugin provides the following configuration options:

ValuesAbsolute true|false
Enables or disables reporting of file handles usage in absolute numbers, e.g. file handles used.
Defaults to true.

ValuesPercentage false|true
Enables or disables reporting of file handles usage in percentages, e.g. percent of file handles
used. Defaults to false.

Plugin "filecount"
The "filecount" plugin counts the number of files in a certain directory (and its subdirectories) and
their combined size. The configuration is very straight forward:

<Plugin "filecount">
<Directory "/var/qmail/queue/mess">
Instance "qmail-message"
</Directory>
<Directory "/var/qmail/queue/todo">
Instance "qmail-todo"
</Directory>
<Directory "/var/lib/php5">
Instance "php5-sessions"
Name "sess_*"
</Directory>
</Plugin>

The example above counts the number of files in QMail's queue directories and the number of PHP5
sessions. Jfiy: The "todo" queue holds the messages that QMail has not yet looked at, the "message" queue
holds the messages that were classified into "local" and "remote".

As you can see, the configuration consists of one or more "Directory" blocks, each of which specifies a
directory in which to count the files. Within those blocks, the following options are recognized:

Instance Instance
Sets the plugin instance to Instance. That instance name must be unique, but it's your
responsibility, the plugin doesn't check for that. If not given, the instance is set to the directory
name with all slashes replaced by underscores and all leading underscores removed.

Name Pattern
Only count files that match Pattern, where Pattern is a shell-like wildcard as understood by
fnmatch(3). Only the filename is checked against the pattern, not the entire path. In case this makes
it easier for you: This option has been named after the -name parameter to find(1).

MTime Age
Count only files of a specific age: If Age is greater than zero, only files that haven't been touched
in the last Age seconds are counted. If Age is a negative number, this is inversed. For example, if
-60 is specified, only files that have been modified in the last minute will be counted.

The number can also be followed by a "multiplier" to easily specify a larger timespan. When given in
this notation, the argument must in quoted, i. e. must be passed as string. So the -60 could also be
written as "-1m" (one minute). Valid multipliers are "s" (second), "m" (minute), "h" (hour), "d"
(day), "w" (week), and "y" (year). There is no "month" multiplier. You can also specify fractional
numbers, e. g. "0.5d" is identical to "12h".

Size Size
Count only files of a specific size. When Size is a positive number, only files that are at least
this big are counted. If Size is a negative number, this is inversed, i. e. only files smaller than
the absolute value of Size are counted.

As with the MTime option, a "multiplier" may be added. For a detailed description see above. Valid
multipliers here are "b" (byte), "k" (kilobyte), "m" (megabyte), "g" (gigabyte), "t" (terabyte), and
"p" (petabyte). Please note that there are 1000 bytes in a kilobyte, not 1024.

Recursive true|false
Controls whether or not to recurse into subdirectories. Enabled by default.

IncludeHidden true|false
Controls whether or not to include "hidden" files and directories in the count. "Hidden" files and
directories are those, whose name begins with a dot. Defaults to false, i.e. by default hidden files
and directories are ignored.

Plugin "GenericJMX"
The GenericJMX plugin is written in Java and therefore documented in collectd-java(5).

Plugin "gmond"
The gmond plugin received the multicast traffic sent by gmond, the statistics collection daemon of
Ganglia. Mappings for the standard "metrics" are built-in, custom mappings may be added via Metric
blocks, see below.

Synopsis:

<Plugin "gmond">
MCReceiveFrom "239.2.11.71" "8649"
<Metric "swap_total">
Type "swap"
TypeInstance "total"
DataSource "value"
</Metric>
<Metric "swap_free">
Type "swap"
TypeInstance "free"
DataSource "value"
</Metric>
</Plugin>

The following metrics are built-in:

• load_one, load_five, load_fifteen

• cpu_user, cpu_system, cpu_idle, cpu_nice, cpu_wio

• mem_free, mem_shared, mem_buffers, mem_cached, mem_total

• bytes_in, bytes_out

• pkts_in, pkts_out

Available configuration options:

MCReceiveFrom MCGroup [Port]
Sets sets the multicast group and UDP port to which to subscribe.

Default: 239.2.11.71 / 8649

<Metric Name>
These blocks add a new metric conversion to the internal table. Name, the string argument to the
Metric block, is the metric name as used by Ganglia.

Type Type
Type to map this metric to. Required.

TypeInstance Instance
Type-instance to use. Optional.

DataSource Name
Data source to map this metric to. If the configured type has exactly one data source, this is
optional. Otherwise the option is required.

Plugin "hddtemp"
To get values from hddtemp collectd connects to localhost (127.0.0.1), port 7634/tcp. The Host and Port
options can be used to change these default values, see below. "hddtemp" has to be running to work
correctly. If "hddtemp" is not running timeouts may appear which may interfere with other statistics..

The hddtemp homepage can be found at <http://www.guzu.net/linux/hddtemp.php>.

Host Hostname
Hostname to connect to. Defaults to 127.0.0.1.

Port Port
TCP-Port to connect to. Defaults to 7634.

Plugin "interface"
Interface Interface
Select this interface. By default these interfaces will then be collected. For a more detailed
description see IgnoreSelected below.

IgnoreSelected true|false
If no configuration if given, the traffic-plugin will collect data from all interfaces. This may not
be practical, especially for loopback- and similar interfaces. Thus, you can use the Interface-option
to pick the interfaces you're interested in. Sometimes, however, it's easier/preferred to collect all
interfaces except a few ones. This option enables you to do that: By setting IgnoreSelected to true
the effect of Interface is inverted: All selected interfaces are ignored and all other interfaces are
collected.

It is possible to use regular expressions to match interface names, if the name is surrounded by
/.../ and collectd was compiled with support for regexps. This is useful if there's a need to collect
(or ignore) data for a group of interfaces that are similarly named, without the need to explicitly
list all of them (especially useful if the list is dynamic). Example:

Interface "lo"
Interface "/^veth/"
Interface "/^tun[0-9]+/"
IgnoreSelected "true"

This will ignore the loopback interface, all interfaces with names starting with veth and all
interfaces with names starting with tun followed by at least one digit.

Plugin "ipmi"
Sensor Sensor
Selects sensors to collect or to ignore, depending on IgnoreSelected.

IgnoreSelected true|false
If no configuration if given, the ipmi plugin will collect data from all sensors found of type
"temperature", "voltage", "current" and "fanspeed". This option enables you to do that: By setting
IgnoreSelected to true the effect of Sensor is inverted: All selected sensors are ignored and all
other sensors are collected.

NotifySensorAdd true|false
If a sensor appears after initialization time of a minute a notification is sent.

NotifySensorRemove true|false
If a sensor disappears a notification is sent.

NotifySensorNotPresent true|false
If you have for example dual power supply and one of them is (un)plugged then a notification is sent.

Plugin "iptables"
Chain Table Chain [Comment|Number [Name]]
Chain6 Table Chain [Comment|Number [Name]]
Select the iptables/ip6tables filter rules to count packets and bytes from.

If only Table and Chain are given, this plugin will collect the counters of all rules which have a
comment-match. The comment is then used as type-instance.

If Comment or Number is given, only the rule with the matching comment or the nth rule will be
collected. Again, the comment (or the number) will be used as the type-instance.

If Name is supplied, it will be used as the type-instance instead of the comment or the number.

Plugin "irq"
Irq Irq
Select this irq. By default these irqs will then be collected. For a more detailed description see
IgnoreSelected below.

IgnoreSelected true|false
If no configuration if given, the irq-plugin will collect data from all irqs. This may not be
practical, especially if no interrupts happen. Thus, you can use the Irq-option to pick the interrupt
you're interested in. Sometimes, however, it's easier/preferred to collect all interrupts except a
few ones. This option enables you to do that: By setting IgnoreSelected to true the effect of Irq is
inverted: All selected interrupts are ignored and all other interrupts are collected.

Plugin "java"
The Java plugin makes it possible to write extensions for collectd in Java. This section only discusses
the syntax and semantic of the configuration options. For more in-depth information on the Java plugin,
please read collectd-java(5).

Synopsis:

<Plugin "java">
JVMArg "-verbose:jni"
JVMArg "-Djava.class.path=/opt/collectd/lib/collectd/bindings/java"
LoadPlugin "org.collectd.java.Foobar"
<Plugin "org.collectd.java.Foobar">
# To be parsed by the plugin
</Plugin>
</Plugin>

Available configuration options:

JVMArg Argument
Argument that is to be passed to the Java Virtual Machine (JVM). This works exactly the way the
arguments to the java binary on the command line work. Execute "java --help" for details.

Please note that all these options must appear before (i. e. above) any other options! When another
option is found, the JVM will be started and later options will have to be ignored!

LoadPlugin JavaClass
Instantiates a new JavaClass object. The constructor of this object very likely then registers one or
more callback methods with the server.

See collectd-java(5) for details.

When the first such option is found, the virtual machine (JVM) is created. This means that all JVMArg
options must appear before (i. e. above) all LoadPlugin options!

Plugin Name
The entire block is passed to the Java plugin as an org.collectd.api.OConfigItem object.

For this to work, the plugin has to register a configuration callback first, see "config callback" in
collectd-java(5). This means, that the Plugin block must appear after the appropriate LoadPlugin
block. Also note, that Name depends on the (Java) plugin registering the callback and is completely
independent from the JavaClass argument passed to LoadPlugin.

Plugin "load"
The Load plugin collects the system load. These numbers give a rough overview over the utilization of a
machine. The system load is defined as the number of runnable tasks in the run-queue and is provided by
many operating systems as a one, five or fifteen minute average.

The following configuration options are available:

ReportRelative false|true
When enabled, system load divided by number of available CPU cores is reported for intervals 1 min, 5
min and 15 min. Defaults to false.

Plugin "logfile"
LogLevel debug|info|notice|warning|err
Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or
err will be written to the logfile.

Please note that debug is only available if collectd has been compiled with debugging support.

File File
Sets the file to write log messages to. The special strings stdout and stderr can be used to write to
the standard output and standard error channels, respectively. This, of course, only makes much sense
when collectd is running in foreground- or non-daemon-mode.

Timestamp true|false
Prefix all lines printed by the current time. Defaults to true.

PrintSeverity true|false
When enabled, all lines are prefixed by the severity of the log message, for example "warning".
Defaults to false.

Note: There is no need to notify the daemon after moving or removing the log file (e. g. when rotating
the logs). The plugin reopens the file for each line it writes.

Plugin "log_logstash"
The log logstash plugin behaves like the logfile plugin but formats messages as JSON events for logstash
to parse and input.

LogLevel debug|info|notice|warning|err
Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or
err will be written to the logfile.

Please note that debug is only available if collectd has been compiled with debugging support.

Note: There is no need to notify the daemon after moving or removing the log file (e. g. when rotating
the logs). The plugin reopens the file for each line it writes.

Plugin "lpar"
The LPAR plugin reads CPU statistics of Logical Partitions, a virtualization technique for IBM POWER
processors. It takes into account CPU time stolen from or donated to a partition, in addition to the
usual user, system, I/O statistics.

The following configuration options are available:

CpuPoolStats false|true
When enabled, statistics about the processor pool are read, too. The partition needs to have pool
authority in order to be able to acquire this information. Defaults to false.

ReportBySerial false|true
If enabled, the serial of the physical machine the partition is currently running on is reported as
hostname and the logical hostname of the machine is reported in the plugin instance. Otherwise, the
logical hostname will be used (just like other plugins) and the plugin instance will be empty.
Defaults to false.

Plugin "mbmon"
The "mbmon plugin" uses mbmon to retrieve temperature, voltage, etc.

Be default collectd connects to localhost (127.0.0.1), port 411/tcp. The Host and Port options can be
used to change these values, see below. "mbmon" has to be running to work correctly. If "mbmon" is not
running timeouts may appear which may interfere with other statistics..

"mbmon" must be run with the -r option ("print TAG and Value format"); Debian's /etc/init.d/mbmon script
already does this, other people will need to ensure that this is the case.

Host Hostname
Hostname to connect to. Defaults to 127.0.0.1.

Port Port
TCP-Port to connect to. Defaults to 411.

Plugin "md"
The "md plugin" collects information from Linux Software-RAID devices (md).

All reported values are of the type "md_disks". Reported type instances are active, failed (present but
not operational), spare (hot stand-by) and missing (physically absent) disks.

Device Device
Select md devices based on device name. The device name is the basename of the device, i.e. the name
of the block device without the leading "/dev/". See IgnoreSelected for more details.

IgnoreSelected true|false
Invert device selection: If set to true, all md devices except those listed using Device are
collected. If false (the default), only those listed are collected. If no configuration is given, the
md plugin will collect data from all md devices.

Plugin "memcachec"
The "memcachec plugin" connects to a memcached server, queries one or more given pages and parses the
returned data according to user specification. The matches used are the same as the matches used in the
"curl" and "tail" plugins.

In order to talk to the memcached server, this plugin uses the libmemcached library. Please note that
there is another library with a very similar name, libmemcache (notice the missing `d'), which is not
applicable.

Synopsis of the configuration:

<Plugin "memcachec">
<Page "plugin_instance">
Server "localhost"
Key "page_key"
<Match>
Regex "(\\d+) bytes sent"
DSType CounterAdd
Type "ipt_octets"
Instance "type_instance"
</Match>
</Page>
</Plugin>

The configuration options are:

<Page Name>
Each Page block defines one page to be queried from the memcached server. The block requires one
string argument which is used as plugin instance.

Server Address
Sets the server address to connect to when querying the page. Must be inside a Page block.

Key Key
When connected to the memcached server, asks for the page Key.

<Match>
Match blocks define which strings to look for and how matches substrings are interpreted. For a
description of match blocks, please see "Plugin tail".

Plugin "memcached"
The memcached plugin connects to a memcached server and queries statistics about cache utilization,
memory and bandwidth used. <http://www.danga.com/memcached/>

<Plugin "memcached">
<Instance "name">
Host "memcache.example.com"
Port 11211
</Instance>
</Plugin>

The plugin configuration consists of one or more Instance blocks which specify one memcached connection
each. Within the Instance blocks, the following options are allowed:

Host Hostname
Hostname to connect to. Defaults to 127.0.0.1.

Port Port
TCP-Port to connect to. Defaults to 11211.

Socket Path
Connect to memcached using the UNIX domain socket at Path. If this setting is given, the Host and
Port settings are ignored.

Plugin "mic"
The mic plugin gathers CPU statistics, memory usage and temperatures from Intel's Many Integrated Core
(MIC) systems.

Synopsis:

<Plugin mic>
ShowCPU true
ShowCPUCores true
ShowMemory true

ShowTemperatures true
Temperature vddg
Temperature vddq
IgnoreSelectedTemperature true

ShowPower true
Power total0
Power total1
IgnoreSelectedPower true
</Plugin>

The following options are valid inside the Plugin mic block:

ShowCPU true|false
If enabled (the default) a sum of the CPU usage across all cores is reported.

ShowCPUCores true|false
If enabled (the default) per-core CPU usage is reported.

ShowMemory true|false
If enabled (the default) the physical memory usage of the MIC system is reported.

ShowTemperatures true|false
If enabled (the default) various temperatures of the MIC system are reported.

Temperature Name
This option controls which temperatures are being reported. Whether matching temperatures are being
ignored or only matching temperatures are reported depends on the IgnoreSelectedTemperature setting
below. By default all temperatures are reported.

IgnoreSelectedTemperature false|true
Controls the behavior of the Temperature setting above. If set to false (the default) only
temperatures matching a Temperature option are reported or, if no Temperature option is specified,
all temperatures are reported. If set to true, matching temperatures are ignored and all other
temperatures are reported.

Known temperature names are:

die Die of the CPU

devmem
Device Memory

fin Fan In

fout
Fan Out

vccp
Voltage ccp

vddg
Voltage ddg

vddq
Voltage ddq

ShowPower true|false
If enabled (the default) various temperatures of the MIC system are reported.

Power Name
This option controls which power readings are being reported. Whether matching power readings are
being ignored or only matching power readings are reported depends on the IgnoreSelectedPower setting
below. By default all power readings are reported.

IgnoreSelectedPower false|true
Controls the behavior of the Power setting above. If set to false (the default) only power readings
matching a Power option are reported or, if no Power option is specified, all power readings are
reported. If set to true, matching power readings are ignored and all other power readings are
reported.

Known power names are:

total0
Total power utilization averaged over Time Window 0 (uWatts).

total1
Total power utilization averaged over Time Window 0 (uWatts).

inst
Instantaneous power (uWatts).

imax
Max instantaneous power (uWatts).

pcie
PCI-E connector power (uWatts).

c2x3
2x3 connector power (uWatts).

c2x4
2x4 connector power (uWatts).

vccp
Core rail (uVolts).

vddg
Uncore rail (uVolts).

vddq
Memory subsystem rail (uVolts).

Plugin "memory"
The memory plugin provides the following configuration options:

ValuesAbsolute true|false
Enables or disables reporting of physical memory usage in absolute numbers, i.e. bytes. Defaults to
true.

ValuesPercentage false|true
Enables or disables reporting of physical memory usage in percentages, e.g. percent of physical
memory used. Defaults to false.

This is useful for deploying collectd in a heterogeneous environment in which the sizes of physical
memory vary.

Plugin "modbus"
The modbus plugin connects to a Modbus "slave" via Modbus/TCP or Modbus/RTU and reads register values. It
supports reading single registers (unsigned 16 bit values), large integer values (unsigned 32 bit values)
and floating point values (two registers interpreted as IEEE floats in big endian notation).

Synopsis:

<Data "voltage-input-1">
RegisterBase 0
RegisterType float
RegisterCmd ReadHolding
Type voltage
Instance "input-1"
</Data>

<Data "voltage-input-2">
RegisterBase 2
RegisterType float
RegisterCmd ReadHolding
Type voltage
Instance "input-2"
</Data>

<Data "supply-temperature-1">
RegisterBase 0
RegisterType Int16
RegisterCmd ReadHolding
Type temperature
Instance "temp-1"
</Data>

<Host "modbus.example.com">
Address "192.168.0.42"
Port "502"
Interval 60

<Slave 1>
Instance "power-supply"
Collect "voltage-input-1"
Collect "voltage-input-2"
</Slave>
</Host>

<Host "localhost">
Device "/dev/ttyUSB0"
Baudrate 38400
Interval 20

<Slave 1>
Instance "temperature"
Collect "supply-temperature-1"
</Slave>
</Host>

<Data Name> blocks
Data blocks define a mapping between register numbers and the "types" used by collectd.

Within <Data /> blocks, the following options are allowed:

RegisterBase Number
Configures the base register to read from the device. If the option RegisterType has been set to
Uint32 or Float, this and the next register will be read (the register number is increased by
one).

RegisterType Int16|Int32|Uint16|Uint32|Float
Specifies what kind of data is returned by the device. If the type is Int32, Uint32 or Float, two
16 bit registers will be read and the data is combined into one value. Defaults to Uint16.

RegisterCmd ReadHolding|ReadInput
Specifies register type to be collected from device. Works only with libmodbus 2.9.2 or higher.
Defaults to ReadHolding.

Type Type
Specifies the "type" (data set) to use when dispatching the value to collectd. Currently, only
data sets with exactly one data source are supported.

Instance Instance
Sets the type instance to use when dispatching the value to collectd. If unset, an empty string
(no type instance) is used.

<Host Name> blocks
Host blocks are used to specify to which hosts to connect and what data to read from their "slaves".
The string argument Name is used as hostname when dispatching the values to collectd.

Within <Host /> blocks, the following options are allowed:

Address Hostname
For Modbus/TCP, specifies the node name (the actual network address) used to connect to the host.
This may be an IP address or a hostname. Please note that the used libmodbus library only
supports IPv4 at the moment.

Port Service
for Modbus/TCP, specifies the port used to connect to the host. The port can either be given as a
number or as a service name. Please note that the Service argument must be a string, even if
ports are given in their numerical form. Defaults to "502".

Device Devicenode
For Modbus/RTU, specifies the path to the serial device being used.

Baudrate Baudrate
For Modbus/RTU, specifies the baud rate of the serial device. Note, connections currently
support only 8/N/1.

Interval Interval
Sets the interval (in seconds) in which the values will be collected from this host. By default
the global Interval setting will be used.

<Slave ID>
Over each connection, multiple Modbus devices may be reached. The slave ID is used to specify
which device should be addressed. For each device you want to query, one Slave block must be
given.

Within <Slave /> blocks, the following options are allowed:

Instance Instance
Specify the plugin instance to use when dispatching the values to collectd. By default
"slave_ID" is used.

Collect DataName
Specifies which data to retrieve from the device. DataName must be the same string as the
Name argument passed to a Data block. You can specify this option multiple times to collect
more than one value from a slave. At least one Collect option is mandatory.

Plugin "mysql"
The "mysql plugin" requires mysqlclient to be installed. It connects to one or more databases when
started and keeps the connection up as long as possible. When the connection is interrupted for whatever
reason it will try to re-connect. The plugin will complain loudly in case anything goes wrong.

This plugin issues the MySQL "SHOW STATUS" / "SHOW GLOBAL STATUS" command and collects information about
MySQL network traffic, executed statements, requests, the query cache and threads by evaluating the
"Bytes_{received,sent}", "Com_*", "Handler_*", "Qcache_*" and "Threads_*" return values. Please refer to
the MySQL reference manual, 5.1.6. Server Status Variables for an explanation of these values.

Optionally, master and slave statistics may be collected in a MySQL replication setup. In that case,
information about the synchronization state of the nodes are collected by evaluating the "Position"
return value of the "SHOW MASTER STATUS" command and the "Seconds_Behind_Master", "Read_Master_Log_Pos"
and "Exec_Master_Log_Pos" return values of the "SHOW SLAVE STATUS" command. See the MySQL reference
manual, 12.5.5.21 SHOW MASTER STATUS Syntax and 12.5.5.31 SHOW SLAVE STATUS Syntax for details.

Synopsis:

<Plugin mysql>
<Database foo>
Host "hostname"
User "username"
Password "password"
Port "3306"
MasterStats true
ConnectTimeout 10
</Database>

<Database bar>
Alias "squeeze"
Host "localhost"
Socket "/var/run/mysql/mysqld.sock"
SlaveStats true
SlaveNotifications true
</Database>
</Plugin>

A Database block defines one connection to a MySQL database. It accepts a single argument which specifies
the name of the database. None of the other options are required. MySQL will use default values as
documented in the section "mysql_real_connect()" in the MySQL reference manual.

Alias Alias
Alias to use as sender instead of hostname when reporting. This may be useful when having cryptic
hostnames.

Host Hostname
Hostname of the database server. Defaults to localhost.

User Username
Username to use when connecting to the database. The user does not have to be granted any privileges
(which is synonym to granting the "USAGE" privilege), unless you want to collectd replication
statistics (see MasterStats and SlaveStats below). In this case, the user needs the "REPLICATION
CLIENT" (or "SUPER") privileges. Else, any existing MySQL user will do.

Password Password
Password needed to log into the database.

Database Database
Select this database. Defaults to no database which is a perfectly reasonable option for what this
plugin does.

Port Port
TCP-port to connect to. The port must be specified in its numeric form, but it must be passed as a
string nonetheless. For example:

Port "3306"

If Host is set to localhost (the default), this setting has no effect. See the documentation for the
"mysql_real_connect" function for details.

Socket Socket
Specifies the path to the UNIX domain socket of the MySQL server. This option only has any effect, if
Host is set to localhost (the default). Otherwise, use the Port option above. See the documentation
for the "mysql_real_connect" function for details.

InnodbStats true|false
If enabled, metrics about the InnoDB storage engine are collected. Disabled by default.

MasterStats true|false
SlaveStats true|false
Enable the collection of master / slave statistics in a replication setup. In order to be able to get
access to these statistics, the user needs special privileges. See the User documentation above.
Defaults to false.

SlaveNotifications true|false
If enabled, the plugin sends a notification if the replication slave I/O and / or SQL threads are not
running. Defaults to false.

ConnectTimeout Seconds
Sets the connect timeout for the MySQL client.

Plugin "netapp"
The netapp plugin can collect various performance and capacity information from a NetApp filer using the
NetApp API.

Please note that NetApp has a wide line of products and a lot of different software versions for each of
these products. This plugin was developed for a NetApp FAS3040 running OnTap 7.2.3P8 and tested on
FAS2050 7.3.1.1L1, FAS3140 7.2.5.1 and FAS3020 7.2.4P9. It should work for most combinations of model and
software version but it is very hard to test this. If you have used this plugin with other models and/or
software version, feel free to send us a mail to tell us about the results, even if it's just a short "It
works".

To collect these data collectd will log in to the NetApp via HTTP(S) and HTTP basic authentication.

Do not use a regular user for this! Create a special collectd user with just the minimum of capabilities
needed. The user only needs the "login-http-admin" capability as well as a few more depending on which
data will be collected. Required capabilities are documented below.

Synopsis

<Plugin "netapp">
<Host "netapp1.example.com">
Protocol "https"
Address "10.0.0.1"
Port 443
User "username"
Password "aef4Aebe"
Interval 30

<WAFL>
Interval 30
GetNameCache true
GetDirCache true
GetBufferCache true
GetInodeCache true
</WAFL>

<Disks>
Interval 30
GetBusy true
</Disks>

<VolumePerf>
Interval 30
GetIO "volume0"
IgnoreSelectedIO false
GetOps "volume0"
IgnoreSelectedOps false
GetLatency "volume0"
IgnoreSelectedLatency false
</VolumePerf>

<VolumeUsage>
Interval 30
GetCapacity "vol0"
GetCapacity "vol1"
IgnoreSelectedCapacity false
GetSnapshot "vol1"
GetSnapshot "vol3"
IgnoreSelectedSnapshot false
</VolumeUsage>

<Quota>
Interval 60
</Quota>

<Snapvault>
Interval 30
</Snapvault>

<System>
Interval 30
GetCPULoad true
GetInterfaces true
GetDiskOps true
GetDiskIO true
</System>

<VFiler vfilerA>
Interval 60

SnapVault true
# ...
</VFiler>
</Host>
</Plugin>

The netapp plugin accepts the following configuration options:

Host Name
A host block defines one NetApp filer. It will appear in collectd with the name you specify here
which does not have to be its real name nor its hostname (see the Address option below).

VFiler Name
A VFiler block may only be used inside a host block. It accepts all the same options as the Host
block (except for cascaded VFiler blocks) and will execute all NetApp API commands in the context of
the specified VFiler(R). It will appear in collectd with the name you specify here which does not
have to be its real name. The VFiler name may be specified using the VFilerName option. If this is
not specified, it will default to the name you specify here.

The VFiler block inherits all connection related settings from the surrounding Host block (which
appear before the VFiler block) but they may be overwritten inside the VFiler block.

This feature is useful, for example, when using a VFiler as SnapVault target (supported since OnTap
8.1). In that case, the SnapVault statistics are not available in the host filer (vfiler0) but only
in the respective VFiler context.

Protocol httpd|http
The protocol collectd will use to query this host.

Optional

Type: string

Default: https

Valid options: http, https

Address Address
The hostname or IP address of the host.

Optional

Type: string

Default: The "host" block's name.

Port Port
The TCP port to connect to on the host.

Optional

Type: integer

Default: 80 for protocol "http", 443 for protocol "https"

User User
Password Password
The username and password to use to login to the NetApp.

Mandatory

Type: string

VFilerName Name
The name of the VFiler in which context to execute API commands. If not specified, the name provided
to the VFiler block will be used instead.

Optional

Type: string

Default: name of the VFiler block

Note: This option may only be used inside VFiler blocks.

Interval Interval
TODO

The following options decide what kind of data will be collected. You can either use them as a block and
fine tune various parameters inside this block, use them as a single statement to just accept all default
values, or omit it to not collect any data.

The following options are valid inside all blocks:

Interval Seconds
Collect the respective statistics every Seconds seconds. Defaults to the host specific setting.

The System block

This will collect various performance data about the whole system.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Interval Seconds
Collect disk statistics every Seconds seconds.

GetCPULoad true|false
If you set this option to true the current CPU usage will be read. This will be the average usage
between all CPUs in your NetApp without any information about individual CPUs.

Note: These are the same values that the NetApp CLI command "sysstat" returns in the "CPU" field.

Optional

Type: boolean

Default: true

Result: Two value lists of type "cpu", and type instances "idle" and "system".

GetInterfaces true|false
If you set this option to true the current traffic of the network interfaces will be read. This will
be the total traffic over all interfaces of your NetApp without any information about individual
interfaces.

Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Net kB/s" field.

Or is it?

Optional

Type: boolean

Default: true

Result: One value list of type "if_octects".

GetDiskIO true|false
If you set this option to true the current IO throughput will be read. This will be the total IO of
your NetApp without any information about individual disks, volumes or aggregates.

Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Disk kB/s" field.

Optional

Type: boolean

Default: true

Result: One value list of type "disk_octets".

GetDiskOps true|false
If you set this option to true the current number of HTTP, NFS, CIFS, FCP, iSCSI, etc. operations
will be read. This will be the total number of operations on your NetApp without any information
about individual volumes or aggregates.

Note: These are the same values that the NetApp CLI command "sysstat" returns in the "NFS", "CIFS",
"HTTP", "FCP" and "iSCSI" fields.

Optional

Type: boolean

Default: true

Result: A variable number of value lists of type "disk_ops_complex". Each type of operation will
result in one value list with the name of the operation as type instance.

The WAFL block

This will collect various performance data about the WAFL file system. At the moment this just means
cache performance.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Note: The interface to get these values is classified as "Diagnostics" by NetApp. This means that it is
not guaranteed to be stable even between minor releases.

Interval Seconds
Collect disk statistics every Seconds seconds.

GetNameCache true|false
Optional

Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "name_cache_hit".

GetDirCache true|false
Optional

Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "find_dir_hit".

GetInodeCache true|false
Optional

Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "inode_cache_hit".

GetBufferCache true|false
Note: This is the same value that the NetApp CLI command "sysstat" returns in the "Cache hit" field.

Optional

Type: boolean

Default: true

Result: One value list of type "cache_ratio" and type instance "buf_hash_hit".

The Disks block

This will collect performance data about the individual disks in the NetApp.

Note: To get this data the collectd user needs the "api-perf-object-get-instances" capability.

Interval Seconds
Collect disk statistics every Seconds seconds.

GetBusy true|false
If you set this option to true the busy time of all disks will be calculated and the value of the
busiest disk in the system will be written.

Note: This is the same values that the NetApp CLI command "sysstat" returns in the "Disk util" field.
Probably.

Optional

Type: boolean

Default: true

Result: One value list of type "percent" and type instance "disk_busy".

The VolumePerf block

This will collect various performance data about the individual volumes.

You can select which data to collect about which volume using the following options. They follow the
standard ignorelist semantic.

Note: To get this data the collectd user needs the api-perf-object-get-instances capability.

Interval Seconds
Collect volume performance data every Seconds seconds.

GetIO Volume
GetOps Volume
GetLatency Volume
Select the given volume for IO, operations or latency statistics collection. The argument is the
name of the volume without the "/vol/" prefix.

Since the standard ignorelist functionality is used here, you can use a string starting and ending
with a slash to specify regular expression matching: To match the volumes "vol0", "vol2" and "vol7",
you can use this regular expression:

GetIO "/^vol[027]$/"

If no regular expression is specified, an exact match is required. Both, regular and exact matching
are case sensitive.

If no volume was specified at all for either of the three options, that data will be collected for
all available volumes.

IgnoreSelectedIO true|false
IgnoreSelectedOps true|false
IgnoreSelectedLatency true|false
When set to true, the volumes selected for IO, operations or latency statistics collection will be
ignored and the data will be collected for all other volumes.

When set to false, data will only be collected for the specified volumes and all other volumes will
be ignored.

If no volumes have been specified with the above Get* options, all volumes will be collected
regardless of the IgnoreSelected* option.

Defaults to false

The VolumeUsage block

This will collect capacity data about the individual volumes.

Note: To get this data the collectd user needs the api-volume-list-info capability.

Interval Seconds
Collect volume usage statistics every Seconds seconds.

GetCapacity VolumeName
The current capacity of the volume will be collected. This will result in two to four value lists,
depending on the configuration of the volume. All data sources are of type "df_complex" with the name
of the volume as plugin_instance.

There will be type_instances "used" and "free" for the number of used and available bytes on the
volume. If the volume has some space reserved for snapshots, a type_instance "snap_reserved" will be
available. If the volume has SIS enabled, a type_instance "sis_saved" will be available. This is the
number of bytes saved by the SIS feature.

Note: The current NetApp API has a bug that results in this value being reported as a 32 bit number.
This plugin tries to guess the correct number which works most of the time. If you see strange
values here, bug NetApp support to fix this.

Repeat this option to specify multiple volumes.

IgnoreSelectedCapacity true|false
Specify whether to collect only the volumes selected by the GetCapacity option or to ignore those
volumes. IgnoreSelectedCapacity defaults to false. However, if no GetCapacity option is specified at
all, all capacities will be selected anyway.

GetSnapshot VolumeName
Select volumes from which to collect snapshot information.

Usually, the space used for snapshots is included in the space reported as "used". If snapshot
information is collected as well, the space used for snapshots is subtracted from the used space.

To make things even more interesting, it is possible to reserve space to be used for snapshots. If
the space required for snapshots is less than that reserved space, there is "reserved free" and
"reserved used" space in addition to "free" and "used". If the space required for snapshots exceeds
the reserved space, that part allocated in the normal space is subtracted from the "used" space
again.

Repeat this option to specify multiple volumes.

IgnoreSelectedSnapshot
Specify whether to collect only the volumes selected by the GetSnapshot option or to ignore those
volumes. IgnoreSelectedSnapshot defaults to false. However, if no GetSnapshot option is specified at
all, all capacities will be selected anyway.

The Quota block

This will collect (tree) quota statistics (used disk space and number of used files). This mechanism is
useful to get usage information for single qtrees. In case the quotas are not used for any other
purpose, an entry similar to the following in "/etc/quotas" would be sufficient:

/vol/volA/some_qtree tree - - - - -

After adding the entry, issue "quota on -w volA" on the NetApp filer.

Interval Seconds
Collect SnapVault(R) statistics every Seconds seconds.

The SnapVault block

This will collect statistics about the time and traffic of SnapVault(R) transfers.

Interval Seconds
Collect SnapVault(R) statistics every Seconds seconds.

Plugin "netlink"
The "netlink" plugin uses a netlink socket to query the Linux kernel about statistics of various
interface and routing aspects.

Interface Interface
VerboseInterface Interface
Instruct the plugin to collect interface statistics. This is basically the same as the statistics
provided by the "interface" plugin (see above) but potentially much more detailed.

When configuring with Interface only the basic statistics will be collected, namely octets, packets,
and errors. These statistics are collected by the "interface" plugin, too, so using both at the same
time is no benefit.

When configured with VerboseInterface all counters except the basic ones, so that no data needs to be
collected twice if you use the "interface" plugin. This includes dropped packets, received multicast
packets, collisions and a whole zoo of differentiated RX and TX errors. You can try the following
command to get an idea of what awaits you:

ip -s -s link list

If Interface is All, all interfaces will be selected.

QDisc Interface [QDisc]
Class Interface [Class]
Filter Interface [Filter]
Collect the octets and packets that pass a certain qdisc, class or filter.

QDiscs and classes are identified by their type and handle (or classid). Filters don't necessarily
have a handle, therefore the parent's handle is used. The notation used in collectd differs from
that used in tc(1) in that it doesn't skip the major or minor number if it's zero and doesn't print
special ids by their name. So, for example, a qdisc may be identified by "pfifo_fast-1:0" even though
the minor number of all qdiscs is zero and thus not displayed by tc(1).

If QDisc, Class, or Filter is given without the second argument, i. .e. without an identifier, all
qdiscs, classes, or filters that are associated with that interface will be collected.

Since a filter itself doesn't necessarily have a handle, the parent's handle is used. This may lead
to problems when more than one filter is attached to a qdisc or class. This isn't nice, but we don't
know how this could be done any better. If you have a idea, please don't hesitate to tell us.

As with the Interface option you can specify All as the interface, meaning all interfaces.

Here are some examples to help you understand the above text more easily:

<Plugin netlink>
VerboseInterface "All"
QDisc "eth0" "pfifo_fast-1:0"
QDisc "ppp0"
Class "ppp0" "htb-1:10"
Filter "ppp0" "u32-1:0"
</Plugin>

IgnoreSelected
The behavior is the same as with all other similar plugins: If nothing is selected at all, everything
is collected. If some things are selected using the options described above, only these statistics
are collected. If you set IgnoreSelected to true, this behavior is inverted, i. e. the specified
statistics will not be collected.

Plugin "network"
The Network plugin sends data to a remote instance of collectd, receives data from a remote instance, or
both at the same time. Data which has been received from the network is usually not transmitted again,
but this can be activated, see the Forward option below.

The default IPv6 multicast group is "ff18::efc0:4a42". The default IPv4 multicast group is 239.192.74.66.
The default UDP port is 25826.

Both, Server and Listen can be used as single option or as block. When used as block, given options are
valid for this socket only. The following example will export the metrics twice: Once to an "internal"
server (without encryption and signing) and one to an external server (with cryptographic signature):

<Plugin "network">
# Export to an internal server
# (demonstrates usage without additional options)
Server "collectd.internal.tld"

# Export to an external server
# (demonstrates usage with signature options)
<Server "collectd.external.tld">
SecurityLevel "sign"
Username "myhostname"
Password "ohl0eQue"
</Server>
</Plugin>

<Server Host [Port]>
The Server statement/block sets the server to send datagrams to. The statement may occur multiple
times to send each datagram to multiple destinations.

The argument Host may be a hostname, an IPv4 address or an IPv6 address. The optional second argument
specifies a port number or a service name. If not given, the default, 25826, is used.

The following options are recognized within Server blocks:

SecurityLevel Encrypt|Sign|None
Set the security you require for network communication. When the security level has been set to
Encrypt, data sent over the network will be encrypted using AES-256. The integrity of encrypted
packets is ensured using SHA-1. When set to Sign, transmitted data is signed using the
HMAC-SHA-256 message authentication code. When set to None, data is sent without any security.

This feature is only available if the network plugin was linked with libgcrypt.

Username Username
Sets the username to transmit. This is used by the server to lookup the password. See AuthFile
below. All security levels except None require this setting.

This feature is only available if the network plugin was linked with libgcrypt.

Password Password
Sets a password (shared secret) for this socket. All security levels except None require this
setting.

This feature is only available if the network plugin was linked with libgcrypt.

Interface Interface name
Set the outgoing interface for IP packets. This applies at least to IPv6 packets and if possible
to IPv4. If this option is not applicable, undefined or a non-existent interface name is
specified, the default behavior is to let the kernel choose the appropriate interface. Be warned
that the manual selection of an interface for unicast traffic is only necessary in rare cases.

ResolveInterval Seconds
Sets the interval at which to re-resolve the DNS for the Host. This is useful to force a regular
DNS lookup to support a high availability setup. If not specified, re-resolves are never
attempted.

<Listen Host [Port]>
The Listen statement sets the interfaces to bind to. When multiple statements are found the daemon
will bind to multiple interfaces.

The argument Host may be a hostname, an IPv4 address or an IPv6 address. If the argument is a
multicast address the daemon will join that multicast group. The optional second argument specifies
a port number or a service name. If not given, the default, 25826, is used.

The following options are recognized within "<Listen>" blocks:

SecurityLevel Encrypt|Sign|None
Set the security you require for network communication. When the security level has been set to
Encrypt, only encrypted data will be accepted. The integrity of encrypted packets is ensured
using SHA-1. When set to Sign, only signed and encrypted data is accepted. When set to None, all
data will be accepted. If an AuthFile option was given (see below), encrypted data is decrypted
if possible.

This feature is only available if the network plugin was linked with libgcrypt.

AuthFile Filename
Sets a file in which usernames are mapped to passwords. These passwords are used to verify
signatures and to decrypt encrypted network packets. If SecurityLevel is set to None, this is
optional. If given, signed data is verified and encrypted packets are decrypted. Otherwise,
signed data is accepted without checking the signature and encrypted data cannot be decrypted.
For the other security levels this option is mandatory.

The file format is very simple: Each line consists of a username followed by a colon and any
number of spaces followed by the password. To demonstrate, an example file could look like this:

user0: foo
user1: bar

Each time a packet is received, the modification time of the file is checked using stat(2). If
the file has been changed, the contents is re-read. While the file is being read, it is locked
using fcntl(2).

Interface Interface name
Set the incoming interface for IP packets explicitly. This applies at least to IPv6 packets and
if possible to IPv4. If this option is not applicable, undefined or a non-existent interface name
is specified, the default behavior is, to let the kernel choose the appropriate interface. Thus
incoming traffic gets only accepted, if it arrives on the given interface.

TimeToLive 1-255
Set the time-to-live of sent packets. This applies to all, unicast and multicast, and IPv4 and IPv6
packets. The default is to not change this value. That means that multicast packets will be sent
with a TTL of 1 (one) on most operating systems.

MaxPacketSize 1024-65535
Set the maximum size for datagrams received over the network. Packets larger than this will be
truncated. Defaults to 1452 bytes, which is the maximum payload size that can be transmitted in one
Ethernet frame using IPv6 / UDP.

On the server side, this limit should be set to the largest value used on any client. Likewise, the
value on the client must not be larger than the value on the server, or data will be lost.

Compatibility: Versions prior to version 4.8 used a fixed sized buffer of 1024 bytes. Versions 4.8,
4.9 and 4.10 used a default value of 1024 bytes to avoid problems when sending data to an older
server.

Forward true|false
If set to true, write packets that were received via the network plugin to the sending sockets. This
should only be activated when the Listen- and Server-statements differ. Otherwise packets may be send
multiple times to the same multicast group. While this results in more network traffic than necessary
it's not a huge problem since the plugin has a duplicate detection, so the values will not loop.

ReportStats true|false
The network plugin cannot only receive and send statistics, it can also create statistics about
itself. Collected data included the number of received and sent octets and packets, the length of the
receive queue and the number of values handled. When set to true, the Network plugin will make these
statistics available. Defaults to false.

Plugin "nginx"
This plugin collects the number of connections and requests handled by the "nginx daemon" (speak:
engine X), a HTTP and mail server/proxy. It queries the page provided by the
"ngx_http_stub_status_module" module, which isn't compiled by default. Please refer to
<http://wiki.codemongers.com/NginxStubStatusModule> for more information on how to compile and configure
nginx and this module.

The following options are accepted by the "nginx plugin":

URL http://host/nginx_status
Sets the URL of the "ngx_http_stub_status_module" output.

User Username
Optional user name needed for authentication.

Password Password
Optional password needed for authentication.

VerifyPeer true|false
Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for
details. Enabled by default.

Timeout Milliseconds
The Timeout option sets the overall timeout for HTTP requests to URL, in milliseconds. By default,
the configured Interval is used to set the timeout.

Plugin "notify_desktop"
This plugin sends a desktop notification to a notification daemon, as defined in the Desktop Notification
Specification. To actually display the notifications, notification-daemon is required and collectd has to
be able to access the X server (i. e., the "DISPLAY" and "XAUTHORITY" environment variables have to be
set correctly) and the D-Bus message bus.

The Desktop Notification Specification can be found at
<http://www.galago-project.org/specs/notification/>.

OkayTimeout timeout
WarningTimeout timeout
FailureTimeout timeout
Set the timeout, in milliseconds, after which to expire the notification for "OKAY", "WARNING" and
"FAILURE" severities respectively. If zero has been specified, the displayed notification will not be
closed at all - the user has to do so herself. These options default to 5000. If a negative number
has been specified, the default is used as well.

Plugin "notify_email"
The notify_email plugin uses the ESMTP library to send notifications to a configured email address.

libESMTP is available from <http://www.stafford.uklinux.net/libesmtp/>.

Available configuration options:

From Address
Email address from which the emails should appear to come from.

Default: "root@localhost"

Recipient Address
Configures the email address(es) to which the notifications should be mailed. May be repeated to
send notifications to multiple addresses.

At least one Recipient must be present for the plugin to work correctly.

SMTPServer Hostname
Hostname of the SMTP server to connect to.

Default: "localhost"

SMTPPort Port
TCP port to connect to.

Default: 25

SMTPUser Username
Username for ASMTP authentication. Optional.

SMTPPassword Password
Password for ASMTP authentication. Optional.

Subject Subject
Subject-template to use when sending emails. There must be exactly two string-placeholders in the
subject, given in the standard printf(3) syntax, i. e. %s. The first will be replaced with the
severity, the second with the hostname.

Default: "Collectd notify: %s@%s"

Plugin "ntpd"
The "ntpd" plugin collects per-peer ntpd data such as time offset and time dispersion.

For talking to ntpd, it mimics what the ntpdc control program does on wire - using mode 7 specific
requests. This mode is deprecated with newer ntpd releases (4.2.7p230 and later). For the "ntpd" plugin
to work correctly with them, the ntp daemon must be explicitly configured to enable mode 7 (which is
disabled by default). Refer to the ntp.conf(5) manual page for details.

Available configuration options for the "ntpd" plugin:

Host Hostname
Hostname of the host running ntpd. Defaults to localhost.

Port Port
UDP-Port to connect to. Defaults to 123.

ReverseLookups true|false
Sets whether or not to perform reverse lookups on peers. Since the name or IP-address may be used in
a filename it is recommended to disable reverse lookups. The default is to do reverse lookups to
preserve backwards compatibility, though.

IncludeUnitID true|false
When a peer is a refclock, include the unit ID in the type instance. Defaults to false for backward
compatibility.

If two refclock peers use the same driver and this is false, the plugin will try to write
simultaneous measurements from both to the same type instance. This will result in error messages in
the log and only one set of measurements making it through.

Plugin "nut"
UPS upsname@hostname[:port]
Add a UPS to collect data from. The format is identical to the one accepted by upsc(8).

Plugin "olsrd"
The olsrd plugin connects to the TCP port opened by the txtinfo plugin of the Optimized Link State
Routing daemon and reads information about the current state of the meshed network.

The following configuration options are understood:

Host Host
Connect to Host. Defaults to "localhost".

Port Port
Specifies the port to connect to. This must be a string, even if you give the port as a number rather
than a service name. Defaults to "2006".

CollectLinks No|Summary|Detail
Specifies what information to collect about links, i. e. direct connections of the daemon queried. If
set to No, no information is collected. If set to Summary, the number of links and the average of all
link quality (LQ) and neighbor link quality (NLQ) values is calculated. If set to Detail LQ and NLQ
are collected per link.

Defaults to Detail.

CollectRoutes No|Summary|Detail
Specifies what information to collect about routes of the daemon queried. If set to No, no
information is collected. If set to Summary, the number of routes and the average metric and ETX is
calculated. If set to Detail metric and ETX are collected per route.

Defaults to Summary.

CollectTopology No|Summary|Detail
Specifies what information to collect about the global topology. If set to No, no information is
collected. If set to Summary, the number of links in the entire topology and the average link quality
(LQ) is calculated. If set to Detail LQ and NLQ are collected for each link in the entire topology.

Defaults to Summary.

Plugin "onewire"
EXPERIMENTAL! See notes below.

The "onewire" plugin uses the owcapi library from the owfs project <http://owfs.org/> to read sensors
connected via the onewire bus.

It can be used in two possible modes - standard or advanced.

In the standard mode only temperature sensors (sensors with the family code 10, 22 and 28 - e.g. DS1820,
DS18S20, DS1920) can be read. If you have other sensors you would like to have included, please send a
sort request to the mailing list. You can select sensors to be read or to be ignored depending on the
option IgnoreSelected). When no list is provided the whole bus is walked and all sensors are read.

Hubs (the DS2409 chips) are working, but read the note, why this plugin is experimental, below.

In the advanced mode you can configure any sensor to be read (only numerical value) using full OWFS path
(e.g. "/uncached/10.F10FCA000800/temperature"). In this mode you have to list all the sensors. Neither
default bus walk nor IgnoreSelected are used here. Address and type (file) is extracted from the path
automatically and should produce compatible structure with the "standard" mode (basically the path is
expected as for example "/uncached/10.F10FCA000800/temperature" where it would extract address part
"F10FCA000800" and the rest after the slash is considered the type - here "temperature"). There are two
advantages to this mode - you can access virtually any sensor (not just temperature), select whether to
use cached or directly read values and it is slighlty faster. The downside is more complex configuration.

The two modes are distinguished automatically by the format of the address. It is not possible to mix
the two modes. Once a full path is detected in any Sensor then the whole addressing (all sensors) is
considered to be this way (and as standard addresses will fail parsing they will be ignored).

Device Device
Sets the device to read the values from. This can either be a "real" hardware device, such as a
serial port or an USB port, or the address of the owserver(1) socket, usually localhost:4304.

Though the documentation claims to automatically recognize the given address format, with
version 2.7p4 we had to specify the type explicitly. So with that version, the following
configuration worked for us:

<Plugin onewire>
Device "-s localhost:4304"
</Plugin>

This directive is required and does not have a default value.

Sensor Sensor
In the standard mode selects sensors to collect or to ignore (depending on IgnoreSelected, see
below). Sensors are specified without the family byte at the beginning, so you have to use for
example "F10FCA000800", and not include the leading 10. family byte and point. When no Sensor is
configured the whole Onewire bus is walked and all supported sensors (see above) are read.

In the advanced mode the Sensor specifies full OWFS path - e.g.
"/uncached/10.F10FCA000800/temperature" (or when cached values are OK
"/10.F10FCA000800/temperature"). IgnoreSelected is not used.

As there can be multiple devices on the bus you can list multiple sensor (use multiple Sensor
elements).

IgnoreSelected true|false
If no configuration is given, the onewire plugin will collect data from all sensors found. This may
not be practical, especially if sensors are added and removed regularly. Sometimes, however, it's
easier/preferred to collect only specific sensors or all sensors except a few specified ones. This
option enables you to do that: By setting IgnoreSelected to true the effect of Sensor is inverted:
All selected interfaces are ignored and all other interfaces are collected.

Used only in the standard mode - see above.

Interval Seconds
Sets the interval in which all sensors should be read. If not specified, the global Interval setting
is used.

EXPERIMENTAL! The "onewire" plugin is experimental, because it doesn't yet work with big setups. It works
with one sensor being attached to one controller, but as soon as you throw in a couple more senors and
maybe a hub or two, reading all values will take more than ten seconds (the default interval). We will
probably add some separate thread for reading the sensors and some cache or something like that, but it's
not done yet. We will try to maintain backwards compatibility in the future, but we can't promise. So in
short: If it works for you: Great! But keep in mind that the config might change, though this is
unlikely. Oh, and if you want to help improving this plugin, just send a short notice to the mailing
list. Thanks :)

Plugin "openldap"
To use the "openldap" plugin you first need to configure the OpenLDAP server correctly. The backend
database "monitor" needs to be loaded and working. See slapd-monitor(5) for the details.

The configuration of the "openldap" plugin consists of one or more Instance blocks. Each block requires
one string argument as the instance name. For example:

<Plugin "openldap">
<Instance "foo">
URL "ldap://localhost/"
</Instance>
<Instance "bar">
URL "ldaps://localhost/"
</Instance>
</Plugin>

The following options are accepted within each Instance block:

URL ldap://host/binddn
Sets the URL to use to connect to the OpenLDAP server. This option is mandatory.

StartTLS true|false
Defines whether TLS must be used when connecting to the OpenLDAP server. Disabled by default.

VerifyHost true|false
Enables or disables peer host name verification. If enabled, the plugin checks if the "Common Name"
or a "Subject Alternate Name" field of the SSL certificate matches the host name provided by the URL
option. If this identity check fails, the connection is aborted. Enabled by default.

CACert File
File that holds one or more SSL certificates. If you want to use TLS/SSL you may possibly need this
option. What CA certificates are checked by default depends on the distribution you use and can be
changed with the usual ldap client configuration mechanisms. See ldap.conf(5) for the details.

Timeout Seconds
Sets the timeout value for ldap operations. Defaults to -1 which results in an infinite timeout.

Version Version
An integer which sets the LDAP protocol version number to use when connecting to the OpenLDAP server.
Defaults to 3 for using LDAPv3.

Plugin "openvpn"
The OpenVPN plugin reads a status file maintained by OpenVPN and gathers traffic statistics about
connected clients.

To set up OpenVPN to write to the status file periodically, use the --status option of OpenVPN. Since
OpenVPN can write two different formats, you need to set the required format, too. This is done by
setting --status-version to 2.

So, in a nutshell you need:

openvpn $OTHER_OPTIONS \
--status "/var/run/openvpn-status" 10 \
--status-version 2

Available options:

StatusFile File
Specifies the location of the status file.

ImprovedNamingSchema true|false
When enabled, the filename of the status file will be used as plugin instance and the client's
"common name" will be used as type instance. This is required when reading multiple status files.
Enabling this option is recommended, but to maintain backwards compatibility this option is disabled
by default.

CollectCompression true|false
Sets whether or not statistics about the compression used by OpenVPN should be collected. This
information is only available in single mode. Enabled by default.

CollectIndividualUsers true|false
Sets whether or not traffic information is collected for each connected client individually. If set
to false, currently no traffic data is collected at all because aggregating this data in a save
manner is tricky. Defaults to true.

CollectUserCount true|false
When enabled, the number of currently connected clients or users is collected. This is especially
interesting when CollectIndividualUsers is disabled, but can be configured independently from that
option. Defaults to false.

Plugin "oracle"
The "oracle" plugin uses the OracleX Call Interface (OCI) to connect to an OracleX Database and lets you
execute SQL statements there. It is very similar to the "dbi" plugin, because it was written around the
same time. See the "dbi" plugin's documentation above for details.

<Plugin oracle>
<Query "out_of_stock">
Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
<Result>
Type "gauge"
# InstancePrefix "foo"
InstancesFrom "category"
ValuesFrom "value"
</Result>
</Query>
<Database "product_information">
ConnectID "db01"
Username "oracle"
Password "secret"
Query "out_of_stock"
</Database>
</Plugin>

Query blocks

The Query blocks are handled identically to the Query blocks of the "dbi" plugin. Please see its
documentation above for details on how to specify queries.

Database blocks

Database blocks define a connection to a database and which queries should be sent to that database. Each
database needs a "name" as string argument in the starting tag of the block. This name will be used as
"PluginInstance" in the values submitted to the daemon. Other than that, that name is not used.

ConnectID ID
Defines the "database alias" or "service name" to connect to. Usually, these names are defined in the
file named "$ORACLE_HOME/network/admin/tnsnames.ora".

Host Host
Hostname to use when dispatching values for this database. Defaults to using the global hostname of
the collectd instance.

Username Username
Username used for authentication.

Password Password
Password used for authentication.

Plugin "perl"
This plugin embeds a Perl-interpreter into collectd and provides an interface to collectd's plugin
system. See collectd-perl(5) for its documentation.

Plugin "pinba"
The Pinba plugin receives profiling information from Pinba, an extension for the PHP interpreter. At the
end of executing a script, i.e. after a PHP-based webpage has been delivered, the extension will send a
UDP packet containing timing information, peak memory usage and so on. The plugin will wait for such
packets, parse them and account the provided information, which is then dispatched to the daemon once per
interval.

Synopsis:

<Plugin pinba>
Address "::0"
Port "30002"
# Overall statistics for the website.
<View "www-total">
Server "www.example.com"
</View>
# Statistics for www-a only
<View "www-a">
Host "www-a.example.com"
Server "www.example.com"
</View>
# Statistics for www-b only
<View "www-b">
Host "www-b.example.com"
Server "www.example.com"
</View>
</Plugin>

The plugin provides the following configuration options:

Address Node
Configures the address used to open a listening socket. By default, plugin will bind to the any
address "::0".

Port Service
Configures the port (service) to bind to. By default the default Pinba port "30002" will be used. The
option accepts service names in addition to port numbers and thus requires a string argument.

<View Name> block
The packets sent by the Pinba extension include the hostname of the server, the server name (the name
of the virtual host) and the script that was executed. Using View blocks it is possible to separate
the data into multiple groups to get more meaningful statistics. Each packet is added to all matching
groups, so that a packet may be accounted for more than once.

Host Host
Matches the hostname of the system the webserver / script is running on. This will contain the
result of the gethostname(2) system call. If not configured, all hostnames will be accepted.

Server Server
Matches the name of the virtual host, i.e. the contents of the $_SERVER["SERVER_NAME"] variable
when within PHP. If not configured, all server names will be accepted.

Script Script
Matches the name of the script name, i.e. the contents of the $_SERVER["SCRIPT_NAME"] variable
when within PHP. If not configured, all script names will be accepted.

Plugin "ping"
The Ping plugin starts a new thread which sends ICMP "ping" packets to the configured hosts periodically
and measures the network latency. Whenever the "read" function of the plugin is called, it submits the
average latency, the standard deviation and the drop rate for each host.

Available configuration options:

Host IP-address
Host to ping periodically. This option may be repeated several times to ping multiple hosts.

Interval Seconds
Sets the interval in which to send ICMP echo packets to the configured hosts. This is not the
interval in which statistics are queries from the plugin but the interval in which the hosts are
"pinged". Therefore, the setting here should be smaller than or equal to the global Interval setting.
Fractional times, such as "1.24" are allowed.

Default: 1.0

Timeout Seconds
Time to wait for a response from the host to which an ICMP packet had been sent. If a reply was not
received after Seconds seconds, the host is assumed to be down or the packet to be dropped. This
setting must be smaller than the Interval setting above for the plugin to work correctly. Fractional
arguments are accepted.

Default: 0.9

TTL 0-255
Sets the Time-To-Live of generated ICMP packets.

SourceAddress host
Sets the source address to use. host may either be a numerical network address or a network hostname.

Device name
Sets the outgoing network device to be used. name has to specify an interface name (e. g. "eth0").
This might not be supported by all operating systems.

MaxMissed Packets
Trigger a DNS resolve after the host has not replied to Packets packets. This enables the use of
dynamic DNS services (like dyndns.org) with the ping plugin.

Default: -1 (disabled)

Plugin "postgresql"
The "postgresql" plugin queries statistics from PostgreSQL databases. It keeps a persistent connection to
all configured databases and tries to reconnect if the connection has been interrupted. A database is
configured by specifying a Database block as described below. The default statistics are collected from
PostgreSQL's statistics collector which thus has to be enabled for this plugin to work correctly. This
should usually be the case by default. See the section "The Statistics Collector" of the PostgreSQL
Documentation for details.

By specifying custom database queries using a Query block as described below, you may collect any data
that is available from some PostgreSQL database. This way, you are able to access statistics of external
daemons which are available in a PostgreSQL database or use future or special statistics provided by
PostgreSQL without the need to upgrade your collectd installation.

Starting with version 5.2, the "postgresql" plugin supports writing data to PostgreSQL databases as well.
This has been implemented in a generic way. You need to specify an SQL statement which will then be
executed by collectd in order to write the data (see below for details). The benefit of that approach is
that there is no fixed database layout. Rather, the layout may be optimized for the current setup.

The PostgreSQL Documentation manual can be found at <http://www.postgresql.org/docs/manuals/>.

<Plugin postgresql>
<Query magic>
Statement "SELECT magic FROM wizard WHERE host = $1;"
Param hostname
<Result>
Type gauge
InstancePrefix "magic"
ValuesFrom magic
</Result>
</Query>

<Query rt36_tickets>
Statement "SELECT COUNT(type) AS count, type \
FROM (SELECT CASE \
WHEN resolved = 'epoch' THEN 'open' \
ELSE 'resolved' END AS type \
FROM tickets) type \
GROUP BY type;"
<Result>
Type counter
InstancePrefix "rt36_tickets"
InstancesFrom "type"
ValuesFrom "count"
</Result>
</Query>

<Writer sqlstore>
Statement "SELECT collectd_insert($1, $2, $3, $4, $5, $6, $7, $8, $9);"
StoreRates true
</Writer>

<Database foo>
Host "hostname"
Port "5432"
User "username"
Password "secret"
SSLMode "prefer"
KRBSrvName "kerberos_service_name"
Query magic
</Database>

<Database bar>
Interval 300
Service "service_name"
Query backend # predefined
Query rt36_tickets
</Database>

<Database qux>
# ...
Writer sqlstore
CommitInterval 10
</Database>
</Plugin>

The Query block defines one database query which may later be used by a database definition. It accepts a
single mandatory argument which specifies the name of the query. The names of all queries have to be
unique (see the MinVersion and MaxVersion options below for an exception to this rule). The following
configuration options are available to define the query:

In each Query block, there is one or more Result blocks. Result blocks define how to handle the values
returned from the query. They define which column holds which value and how to dispatch that value to the
daemon. Multiple Result blocks may be used to extract multiple values from a single query.

Statement sql query statement
Specify the sql query statement which the plugin should execute. The string may contain the tokens
$1, $2, etc. which are used to reference the first, second, etc. parameter. The value of the
parameters is specified by the Param configuration option - see below for details. To include a
literal $ character followed by a number, surround it with single quotes (').

Any SQL command which may return data (such as "SELECT" or "SHOW") is allowed. Note, however, that
only a single command may be used. Semicolons are allowed as long as a single non-empty command has
been specified only.

The returned lines will be handled separately one after another.

Param hostname|database|username|interval
Specify the parameters which should be passed to the SQL query. The parameters are referred to in the
SQL query as $1, $2, etc. in the same order as they appear in the configuration file. The value of
the parameter is determined depending on the value of the Param option as follows:

hostname
The configured hostname of the database connection. If a UNIX domain socket is used, the
parameter expands to "localhost".

database
The name of the database of the current connection.

instance
The name of the database plugin instance. See the Instance option of the database specification
below for details.

username
The username used to connect to the database.

interval
The interval with which this database is queried (as specified by the database specific or global
Interval options).

Please note that parameters are only supported by PostgreSQL's protocol version 3 and above which was
introduced in version 7.4 of PostgreSQL.

Type type
The type name to be used when dispatching the values. The type describes how to handle the data and
where to store it. See types.db(5) for more details on types and their configuration. The number and
type of values (as selected by the ValuesFrom option) has to match the type of the given name.

This option is required inside a Result block.

InstancePrefix prefix
InstancesFrom column0 [column1 ...]
Specify how to create the "TypeInstance" for each data set (i. e. line). InstancePrefix defines a
static prefix that will be prepended to all type instances. InstancesFrom defines the column names
whose values will be used to create the type instance. Multiple values will be joined together using
the hyphen ("-") as separation character.

The plugin itself does not check whether or not all built instances are different. It is your
responsibility to assure that each is unique.

Both options are optional. If none is specified, the type instance will be empty.

ValuesFrom column0 [column1 ...]
Names the columns whose content is used as the actual data for the data sets that are dispatched to
the daemon. How many such columns you need is determined by the Type setting as explained above. If
you specify too many or not enough columns, the plugin will complain about that and no data will be
submitted to the daemon.

The actual data type, as seen by PostgreSQL, is not that important as long as it represents numbers.
The plugin will automatically cast the values to the right type if it know how to do that. For that,
it uses the strtoll(3) and strtod(3) functions, so anything supported by those functions is supported
by the plugin as well.

This option is required inside a Result block and may be specified multiple times. If multiple
ValuesFrom options are specified, the columns are read in the given order.

MinVersion version
MaxVersion version
Specify the minimum or maximum version of PostgreSQL that this query should be used with. Some
statistics might only be available with certain versions of PostgreSQL. This allows you to specify
multiple queries with the same name but which apply to different versions, thus allowing you to use
the same configuration in a heterogeneous environment.

The version has to be specified as the concatenation of the major, minor and patch-level versions,
each represented as two-decimal-digit numbers. For example, version 8.2.3 will become 80203.

The following predefined queries are available (the definitions can be found in the
postgresql_default.conf file which, by default, is available at "prefix/share/collectd/"):

backends
This query collects the number of backends, i. e. the number of connected clients.

transactions
This query collects the numbers of committed and rolled-back transactions of the user tables.

queries
This query collects the numbers of various table modifications (i. e. insertions, updates,
deletions) of the user tables.

query_plans
This query collects the numbers of various table scans and returned tuples of the user tables.

table_states
This query collects the numbers of live and dead rows in the user tables.

disk_io
This query collects disk block access counts for user tables.

disk_usage
This query collects the on-disk size of the database in bytes.

In addition, the following detailed queries are available by default. Please note that each of those
queries collects information by table, thus, potentially producing a lot of data. For details see the
description of the non-by_table queries above.

queries_by_table
query_plans_by_table
table_states_by_table
disk_io_by_table

The Writer block defines a PostgreSQL writer backend. It accepts a single mandatory argument specifying
the name of the writer. This will then be used in the Database specification in order to activate the
writer instance. The names of all writers have to be unique. The following options may be specified:

Statement sql statement
This mandatory option specifies the SQL statement that will be executed for each submitted value. A
single SQL statement is allowed only. Anything after the first semicolon will be ignored.

Nine parameters will be passed to the statement and should be specified as tokens $1, $2, through $9
in the statement string. The following values are made available through those parameters:

$1 The timestamp of the queried value as a floating point number.

$2 The hostname of the queried value.

$3 The plugin name of the queried value.

$4 The plugin instance of the queried value. This value may be NULL if there is no plugin instance.

$5 The type of the queried value (cf. types.db(5)).

$6 The type instance of the queried value. This value may be NULL if there is no type instance.

$7 An array of names for the submitted values (i. e., the name of the data sources of the submitted
value-list).

$8 An array of types for the submitted values (i. e., the type of the data sources of the submitted
value-list; "counter", "gauge", ...). Note, that if StoreRates is enabled (which is the default,
see below), all types will be "gauge".

$9 An array of the submitted values. The dimensions of the value name and value arrays match.

In general, it is advisable to create and call a custom function in the PostgreSQL database for this
purpose. Any procedural language supported by PostgreSQL will do (see chapter "Server Programming" in
the PostgreSQL manual for details).

StoreRates false|true
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i. e. as an increasing integer number.

The Database block defines one PostgreSQL database for which to collect statistics. It accepts a single
mandatory argument which specifies the database name. None of the other options are required. PostgreSQL
will use default values as documented in the section "CONNECTING TO A DATABASE" in the psql(1) manpage.
However, be aware that those defaults may be influenced by the user collectd is run as and special
environment variables. See the manpage for details.

Interval seconds
Specify the interval with which the database should be queried. The default is to use the global
Interval setting.

CommitInterval seconds
This option may be used for database connections which have "writers" assigned (see above). If
specified, it causes a writer to put several updates into a single transaction. This transaction will
last for the specified amount of time. By default, each update will be executed in a separate
transaction. Each transaction generates a fair amount of overhead which can, thus, be reduced by
activating this option. The draw-back is, that data covering the specified amount of time will be
lost, for example, if a single statement within the transaction fails or if the database server
crashes.

Instance name
Specify the plugin instance name that should be used instead of the database name (which is the
default, if this option has not been specified). This allows to query multiple databases of the same
name on the same host (e.g. when running multiple database server versions in parallel).

Host hostname
Specify the hostname or IP of the PostgreSQL server to connect to. If the value begins with a slash,
it is interpreted as the directory name in which to look for the UNIX domain socket.

This option is also used to determine the hostname that is associated with a collected data set. If
it has been omitted or either begins with with a slash or equals localhost it will be replaced with
the global hostname definition of collectd. Any other value will be passed literally to collectd when
dispatching values. Also see the global Hostname and FQDNLookup options.

Port port
Specify the TCP port or the local UNIX domain socket file extension of the server.

User username
Specify the username to be used when connecting to the server.

Password password
Specify the password to be used when connecting to the server.

ExpireDelay delay
Skip expired values in query output.

SSLMode disable|allow|prefer|require
Specify whether to use an SSL connection when contacting the server. The following modes are
supported:

disable
Do not use SSL at all.

allow
First, try to connect without using SSL. If that fails, try using SSL.

prefer (default)
First, try to connect using SSL. If that fails, try without using SSL.

require
Use SSL only.

KRBSrvName kerberos_service_name
Specify the Kerberos service name to use when authenticating with Kerberos 5 or GSSAPI. See the
sections "Kerberos authentication" and "GSSAPI" of the PostgreSQL Documentation for details.

Service service_name
Specify the PostgreSQL service name to use for additional parameters. That service has to be defined
in pg_service.conf and holds additional connection parameters. See the section "The Connection
Service File" in the PostgreSQL Documentation for details.

Query query
Specifies a query which should be executed in the context of the database connection. This may be any
of the predefined or user-defined queries. If no such option is given, it defaults to "backends",
"transactions", "queries", "query_plans", "table_states", "disk_io" and "disk_usage" (unless a Writer
has been specified). Else, the specified queries are used only.

Writer writer
Assigns the specified writer backend to the database connection. This causes all collected data to be
send to the database using the settings defined in the writer configuration (see the section "FILTER
CONFIGURATION" below for details on how to selectively send data to certain plugins).

Each writer will register a flush callback which may be used when having long transactions enabled
(see the CommitInterval option above). When issuing the FLUSH command (see collectd-unixsock(5) for
details) the current transaction will be committed right away. Two different kinds of flush callbacks
are available with the "postgresql" plugin:

postgresql
Flush all writer backends.

postgresql-database
Flush all writers of the specified database only.

Plugin "powerdns"
The "powerdns" plugin queries statistics from an authoritative PowerDNS nameserver and/or a PowerDNS
recursor. Since both offer a wide variety of values, many of which are probably meaningless to most
users, but may be useful for some. So you may chose which values to collect, but if you don't, some
reasonable defaults will be collected.

<Plugin "powerdns">
<Server "server_name">
Collect "latency"
Collect "udp-answers" "udp-queries"
Socket "/var/run/pdns.controlsocket"
</Server>
<Recursor "recursor_name">
Collect "questions"
Collect "cache-hits" "cache-misses"
Socket "/var/run/pdns_recursor.controlsocket"
</Recursor>
LocalSocket "/opt/collectd/var/run/collectd-powerdns"
</Plugin>

Server and Recursor block
The Server block defines one authoritative server to query, the Recursor does the same for an
recursing server. The possible options in both blocks are the same, though. The argument defines a
name for the server / recursor and is required.

Collect Field
Using the Collect statement you can select which values to collect. Here, you specify the name of
the values as used by the PowerDNS servers, e. g. "dlg-only-drops", "answers10-100".

The method of getting the values differs for Server and Recursor blocks: When querying the server
a "SHOW *" command is issued in any case, because that's the only way of getting multiple values
out of the server at once. collectd then picks out the values you have selected. When querying
the recursor, a command is generated to query exactly these values. So if you specify invalid
fields when querying the recursor, a syntax error may be returned by the daemon and collectd may
not collect any values at all.

If no Collect statement is given, the following Server values will be collected:

latency
packetcache-hit
packetcache-miss
packetcache-size
query-cache-hit
query-cache-miss
recursing-answers
recursing-questions
tcp-answers
tcp-queries
udp-answers
udp-queries

The following Recursor values will be collected by default:

noerror-answers
nxdomain-answers
servfail-answers
sys-msec
user-msec
qa-latency
cache-entries
cache-hits
cache-misses
questions

Please note that up to that point collectd doesn't know what values are available on the server
and values that are added do not need a change of the mechanism so far. However, the values must
be mapped to collectd's naming scheme, which is done using a lookup table that lists all known
values. If values are added in the future and collectd does not know about them, you will get an
error much like this:

powerdns plugin: submit: Not found in lookup table: foobar = 42

In this case please file a bug report with the collectd team.

Socket Path
Configures the path to the UNIX domain socket to be used when connecting to the daemon. By
default "${localstatedir}/run/pdns.controlsocket" will be used for an authoritative server and
"${localstatedir}/run/pdns_recursor.controlsocket" will be used for the recursor.

LocalSocket Path
Querying the recursor is done using UDP. When using UDP over UNIX domain sockets, the client socket
needs a name in the file system, too. You can set this local name to Path using the LocalSocket
option. The default is "prefix/var/run/collectd-powerdns".

Plugin "processes"
Process Name
Select more detailed statistics of processes matching this name. The statistics collected for these
selected processes are size of the resident segment size (RSS), user- and system-time used, number of
processes and number of threads, io data (where available) and minor and major pagefaults.

ProcessMatch name regex
Similar to the Process option this allows to select more detailed statistics of processes matching
the specified regex (see regex(7) for details). The statistics of all matching processes are summed
up and dispatched to the daemon using the specified name as an identifier. This allows to "group"
several processes together. name must not contain slashes.

Plugin "protocols"
Collects a lot of information about various network protocols, such as IP, TCP, UDP, etc.

Available configuration options:

Value Selector
Selects whether or not to select a specific value. The string being matched is of the form
"Protocol:ValueName", where Protocol will be used as the plugin instance and ValueName will be used
as type instance. An example of the string being used would be "Tcp:RetransSegs".

You can use regular expressions to match a large number of values with just one configuration option.
To select all "extended" TCP values, you could use the following statement:

Value "/^TcpExt:/"

Whether only matched values are selected or all matched values are ignored depends on the
IgnoreSelected. By default, only matched values are selected. If no value is configured at all, all
values will be selected.

IgnoreSelected true|false
If set to true, inverts the selection made by Value, i. e. all matching values will be ignored.

Plugin "python"
This plugin embeds a Python-interpreter into collectd and provides an interface to collectd's plugin
system. See collectd-python(5) for its documentation.

Plugin "routeros"
The "routeros" plugin connects to a device running RouterOS, the Linux-based operating system for routers
by MikroTik. The plugin uses librouteros to connect and reads information about the interfaces and
wireless connections of the device. The configuration supports querying multiple routers:

<Plugin "routeros">
<Router>
Host "router0.example.com"
User "collectd"
Password "secr3t"
CollectInterface true
CollectCPULoad true
CollectMemory true
</Router>
<Router>
Host "router1.example.com"
User "collectd"
Password "5ecret"
CollectInterface true
CollectRegistrationTable true
CollectDF true
CollectDisk true
</Router>
</Plugin>

As you can see above, the configuration of the routeros plugin consists of one or more <Router> blocks.
Within each block, the following options are understood:

Host Host
Hostname or IP-address of the router to connect to.

Port Port
Port name or port number used when connecting. If left unspecified, the default will be chosen by
librouteros, currently "8728". This option expects a string argument, even when a numeric port number
is given.

User User
Use the user name User to authenticate. Defaults to "admin".

Password Password
Set the password used to authenticate.

CollectInterface true|false
When set to true, interface statistics will be collected for all interfaces present on the device.
Defaults to false.

CollectRegistrationTable true|false
When set to true, information about wireless LAN connections will be collected. Defaults to false.

CollectCPULoad true|false
When set to true, information about the CPU usage will be collected. The number is a dimensionless
value where zero indicates no CPU usage at all. Defaults to false.

CollectMemory true|false
When enabled, the amount of used and free memory will be collected. How used memory is calculated is
unknown, for example whether or not caches are counted as used space. Defaults to false.

CollectDF true|false
When enabled, the amount of used and free disk space will be collected. Defaults to false.

CollectDisk true|false
When enabled, the number of sectors written and bad blocks will be collected. Defaults to false.

Plugin "redis"
The Redis plugin connects to one or more Redis servers and gathers information about each server's state.
For each server there is a Node block which configures the connection parameters for this node.

<Plugin redis>
<Node "example">
Host "localhost"
Port "6379"
Timeout 2000
<Query "LLEN myqueue">
Type "queue_length"
Instance "myqueue"
<Query>
</Node>
</Plugin>

The information shown in the synopsis above is the default configuration which is used by the plugin if
no configuration is present.

Node Nodename
The Node block identifies a new Redis node, that is a new Redis instance running in an specified host
and port. The name for node is a canonical identifier which is used as plugin instance. It is limited
to 64 characters in length.

Host Hostname
The Host option is the hostname or IP-address where the Redis instance is running on.

Port Port
The Port option is the TCP port on which the Redis instance accepts connections. Either a service
name of a port number may be given. Please note that numerical port numbers must be given as a
string, too.

Password Password
Use Password to authenticate when connecting to Redis.

Timeout Milliseconds
The Timeout option set the socket timeout for node response. Since the Redis read function is
blocking, you should keep this value as low as possible. Keep in mind that the sum of all Timeout
values for all Nodes should be lower than Interval defined globally.

Query Querystring
The Query block identifies a query to execute against the redis server. There may be an arbitrary
number of queries to execute.

Type Collectd type
Within a query definition, a valid collectd type to use as when submitting the result of the query.
When not supplied, will default to gauge.

Instance Type instance
Within a query definition, an optional type instance to use when submitting the result of the query.
When not supplied will default to the escaped command, up to 64 chars.

Plugin "rrdcached"
The "rrdcached" plugin uses the RRDtool accelerator daemon, rrdcached(1), to store values to RRD files in
an efficient manner. The combination of the "rrdcached" plugin and the "rrdcached" daemon is very similar
to the way the "rrdtool" plugin works (see below). The added abstraction layer provides a number of
benefits, though: Because the cache is not within "collectd" anymore, it does not need to be flushed when
"collectd" is to be restarted. This results in much shorter (if any) gaps in graphs, especially under
heavy load. Also, the "rrdtool" command line utility is aware of the daemon so that it can flush values
to disk automatically when needed. This allows to integrate automated flushing of values into graphing
solutions much more easily.

There are disadvantages, though: The daemon may reside on a different host, so it may not be possible for
"collectd" to create the appropriate RRD files anymore. And even if "rrdcached" runs on the same host, it
may run in a different base directory, so relative paths may do weird stuff if you're not careful.

So the recommended configuration is to let "collectd" and "rrdcached" run on the same host, communicating
via a UNIX domain socket. The DataDir setting should be set to an absolute path, so that a changed base
directory does not result in RRD files being created / expected in the wrong place.

DaemonAddress Address
Address of the daemon as understood by the "rrdc_connect" function of the RRD library. See
rrdcached(1) for details. Example:

<Plugin "rrdcached">
DaemonAddress "unix:/var/run/rrdcached.sock"
</Plugin>

DataDir Directory
Set the base directory in which the RRD files reside. If this is a relative path, it is relative to
the working base directory of the "rrdcached" daemon! Use of an absolute path is recommended.

CreateFiles true|false
Enables or disables the creation of RRD files. If the daemon is not running locally, or DataDir is
set to a relative path, this will not work as expected. Default is true.

CreateFilesAsync false|true
When enabled, new RRD files are enabled asynchronously, using a separate thread that runs in the
background. This prevents writes to block, which is a problem especially when many hundreds of files
need to be created at once. However, since the purpose of creating the files asynchronously is not to
block until the file is available, values before the file is available will be discarded. When
disabled (the default) files are created synchronously, blocking for a short while, while the file is
being written.

StepSize Seconds
Force the stepsize of newly created RRD-files. Ideally (and per default) this setting is unset and
the stepsize is set to the interval in which the data is collected. Do not use this option unless you
absolutely have to for some reason. Setting this option may cause problems with the "snmp plugin",
the "exec plugin" or when the daemon is set up to receive data from other hosts.

HeartBeat Seconds
Force the heartbeat of newly created RRD-files. This setting should be unset in which case the
heartbeat is set to twice the StepSize which should equal the interval in which data is collected. Do
not set this option unless you have a very good reason to do so.

RRARows NumRows
The "rrdtool plugin" calculates the number of PDPs per CDP based on the StepSize, this setting and a
timespan. This plugin creates RRD-files with three times five RRAs, i. e. five RRAs with the CFs MIN,
AVERAGE, and MAX. The five RRAs are optimized for graphs covering one hour, one day, one week, one
month, and one year.

So for each timespan, it calculates how many PDPs need to be consolidated into one CDP by
calculating:
number of PDPs = timespan / (stepsize * rrarows)

Bottom line is, set this no smaller than the width of you graphs in pixels. The default is 1200.

RRATimespan Seconds
Adds an RRA-timespan, given in seconds. Use this option multiple times to have more then one RRA. If
this option is never used, the built-in default of (3600, 86400, 604800, 2678400, 31622400) is used.

For more information on how RRA-sizes are calculated see RRARows above.

XFF Factor
Set the "XFiles Factor". The default is 0.1. If unsure, don't set this option. Factor must be in the
range "[0.0-1.0)", i.e. between zero (inclusive) and one (exclusive).

CollectStatistics false|true
When set to true, various statistics about the rrdcached daemon will be collected, with "rrdcached"
as the plugin name. Defaults to false.

Statistics are read via rrdcacheds socket using the STATS command. See rrdcached(1) for details.

Plugin "rrdtool"
You can use the settings StepSize, HeartBeat, RRARows, and XFF to fine-tune your RRD-files. Please read
rrdcreate(1) if you encounter problems using these settings. If you don't want to dive into the depths of
RRDtool, you can safely ignore these settings.

DataDir Directory
Set the directory to store RRD files under. By default RRD files are generated beneath the daemon's
working directory, i.e. the BaseDir.

RRARows NumRows
The "rrdtool plugin" calculates the number of PDPs per CDP based on the StepSize, this setting and a
timespan. This plugin creates RRD-files with three times five RRAs, i.e. five RRAs with the CFs MIN,
AVERAGE, and MAX. The five RRAs are optimized for graphs covering one hour, one day, one week, one
month, and one year.

So for each timespan, it calculates how many PDPs need to be consolidated into one CDP by
calculating:
number of PDPs = timespan / (stepsize * rrarows)

Bottom line is, set this no smaller than the width of you graphs in pixels. The default is 1200.

For more information on how RRA-sizes are calculated see RRARows above.

XFF Factor
Set the "XFiles Factor". The default is 0.1. If unsure, don't set this option. Factor must be in the
range "[0.0-1.0)", i.e. between zero (inclusive) and one (exclusive).

CacheFlush Seconds
When the "rrdtool" plugin uses a cache (by setting CacheTimeout, see below) it writes all values for
a certain RRD-file if the oldest value is older than (or equal to) the number of seconds specified.
If some RRD-file is not updated anymore for some reason (the computer was shut down, the network is
broken, etc.) some values may still be in the cache. If CacheFlush is set, then the entire cache is
searched for entries older than CacheTimeout seconds and written to disk every Seconds seconds. Since
this is kind of expensive and does nothing under normal circumstances, this value should not be too
small. 900 seconds might be a good value, though setting this to 7200 seconds doesn't normally do
much harm either.

CacheTimeout Seconds
If this option is set to a value greater than zero, the "rrdtool plugin" will save values in a cache,
as described above. Writing multiple values at once reduces IO-operations and thus lessens the load
produced by updating the files. The trade off is that the graphs kind of "drag behind" and that more
memory is used.

WritesPerSecond Updates
When collecting many statistics with collectd and the "rrdtool" plugin, you will run serious
performance problems. The CacheFlush setting and the internal update queue assert that collectd
continues to work just fine even under heavy load, but the system may become very unresponsive and
slow. This is a problem especially if you create graphs from the RRD files on the same machine, for
example using the "graph.cgi" script included in the "contrib/collection3/" directory.

This setting is designed for very large setups. Setting this option to a value between 25 and 80
updates per second, depending on your hardware, will leave the server responsive enough to draw
graphs even while all the cached values are written to disk. Flushed values, i. e. values that are
forced to disk by the FLUSH command, are not effected by this limit. They are still written as fast
as possible, so that web frontends have up to date data when generating graphs.

For example: If you have 100,000 RRD files and set WritesPerSecond to 30 updates per second, writing
all values to disk will take approximately 56 minutes. Together with the flushing ability that's
integrated into "collection3" you'll end up with a responsive and fast system, up to date graphs and
basically a "backup" of your values every hour.

RandomTimeout Seconds
When set, the actual timeout for each value is chosen randomly between CacheTimeout-RandomTimeout and
CacheTimeout+RandomTimeout. The intention is to avoid high load situations that appear when many
values timeout at the same time. This is especially a problem shortly after the daemon starts,
because all values were added to the internal cache at roughly the same time.

Plugin "sensors"
The Sensors plugin uses lm_sensors to retrieve sensor-values. This means that all the needed modules have
to be loaded and lm_sensors has to be configured (most likely by editing /etc/sensors.conf. Read
sensors.conf(5) for details.

The lm_sensors homepage can be found at <http://secure.netroedge.com/~lm78/>.

SensorConfigFile File
Read the lm_sensors configuration from File. When unset (recommended), the library's default will be
used.

Sensor chip-bus-address/type-feature
Selects the name of the sensor which you want to collect or ignore, depending on the IgnoreSelected
below. For example, the option "Sensor it8712-isa-0290/voltage-in1" will cause collectd to gather
data for the voltage sensor in1 of the it8712 on the isa bus at the address 0290.

IgnoreSelected true|false
If no configuration if given, the sensors-plugin will collect data from all sensors. This may not be
practical, especially for uninteresting sensors. Thus, you can use the Sensor-option to pick the
sensors you're interested in. Sometimes, however, it's easier/preferred to collect all sensors except
a few ones. This option enables you to do that: By setting IgnoreSelected to true the effect of
Sensor is inverted: All selected sensors are ignored and all other sensors are collected.

Plugin "sigrok"
The sigrok plugin uses libsigrok to retrieve measurements from any device supported by the sigrok
<http://sigrok.org/> project.

Synopsis

<Plugin sigrok>
LogLevel 3
<Device "AC Voltage">
Driver "fluke-dmm"
MinimumInterval 10
Conn "/dev/ttyUSB2"
</Device>
<Device "Sound Level">
Driver "cem-dt-885x"
Conn "/dev/ttyUSB1"
</Device>
</Plugin>

LogLevel 0-5
The sigrok logging level to pass on to the collectd log, as a number between 0 and 5 (inclusive).
These levels correspond to "None", "Errors", "Warnings", "Informational", "Debug "and "Spew",
respectively. The default is 2 ("Warnings"). The sigrok log messages, regardless of their level, are
always submitted to collectd at its INFO log level.

<Device Name>
A sigrok-supported device, uniquely identified by this section's options. The Name is passed to
collectd as the plugin instance.

Driver DriverName
The sigrok driver to use for this device.

Conn ConnectionSpec
If the device cannot be auto-discovered, or more than one might be discovered by the driver,
ConnectionSpec specifies the connection string to the device. It can be of the form of a device path
(e.g. "/dev/ttyUSB2"), or, in case of a non-serial USB-connected device, the USB VendorID.ProductID
separated by a period (e.g. 0403.6001). A USB device can also be specified as Bus.Address
(e.g. 1.41).

SerialComm SerialSpec
For serial devices with non-standard port settings, this option can be used to specify them in a form
understood by sigrok, e.g. "9600/8n1". This should not be necessary; drivers know how to communicate
with devices they support.

MinimumInterval Seconds
Specifies the minimum time between measurement dispatches to collectd, in seconds. Since some sigrok
supported devices can acquire measurements many times per second, it may be necessary to throttle
these. For example, the RRD plugin cannot process writes more than once per second.

The default MinimumInterval is 0, meaning measurements received from the device are always dispatched
to collectd. When throttled, unused measurements are discarded.

Plugin "smart"
The "smart" plugin collects SMART information from physical disks. Values collectd include temperature,
power cycle count, poweron time and bad sectors. Also, all SMART attributes are collected along with the
normalized current value, the worst value, the threshold and a human readable value.

Using the following two options you can ignore some disks or configure the collection only of specific
disks.

Disk "sdd"
Disk "/hda[34]/"

Plugin "snmp"
Since the configuration of the "snmp plugin" is a little more complicated than other plugins, its
documentation has been moved to an own manpage, collectd-snmp(5). Please see there for details.

Plugin "statsd"
The statsd plugin listens to a UDP socket, reads "events" in the statsd protocol and dispatches rates or
other aggregates of these numbers periodically.

The plugin implements the Counter, Timer, Gauge and Set types which are dispatched as the collectd types
"derive", "latency", "gauge" and "objects" respectively.

The following configuration options are valid:

Host Host
Bind to the hostname / address Host. By default, the plugin will bind to the "any" address, i.e.
accept packets sent to any of the hosts addresses.

Port Port
UDP port to listen to. This can be either a service name or a port number. Defaults to 8125.

DeleteCounters false|true
DeleteTimers false|true
DeleteGauges false|true
DeleteSets false|true
These options control what happens if metrics are not updated in an interval. If set to False, the
default, metrics are dispatched unchanged, i.e. the rate of counters and size of sets will be zero,
timers report "NaN" and gauges are unchanged. If set to True, the such metrics are not dispatched and
removed from the internal cache.

TimerPercentile Percent
Calculate and dispatch the configured percentile, i.e. compute the latency, so that Percent of all
reported timers are smaller than or equal to the computed latency. This is useful for cutting off the
long tail latency, as it's often done in Service Level Agreements (SLAs).

Different percentiles can be calculated by setting this option several times. If none are specified,
no percentiles are calculated / dispatched.

TimerLower false|true
TimerUpper false|true
TimerSum false|true
TimerCount false|true
Calculate and dispatch various values out of Timer metrics received during an interval. If set to
False, the default, these values aren't calculated / dispatched.

Plugin "swap"
The Swap plugin collects information about used and available swap space. On Linux and Solaris, the
following options are available:

ReportByDevice false|true
Configures how to report physical swap devices. If set to false (the default), the summary over all
swap devices is reported only, i.e. the globally used and available space over all devices. If true
is configured, the used and available space of each device will be reported separately.

This option is only available if the Swap plugin can read "/proc/swaps" (under Linux) or use the
swapctl(2) mechanism (under Solaris).

ReportBytes false|true
When enabled, the swap I/O is reported in bytes. When disabled, the default, swap I/O is reported in
pages. This option is available under Linux only.

ValuesAbsolute true|false
Enables or disables reporting of absolute swap metrics, i.e. number of bytes available and used.
Defaults to true.

ValuesPercentage false|true
Enables or disables reporting of relative swap metrics, i.e. percent available and free. Defaults to
false.

This is useful for deploying collectd in a heterogeneous environment, where swap sizes differ and you
want to specify generic thresholds or similar.

Plugin "syslog"
LogLevel debug|info|notice|warning|err
Sets the log-level. If, for example, set to notice, then all events with severity notice, warning, or
err will be submitted to the syslog-daemon.

Please note that debug is only available if collectd has been compiled with debugging support.

NotifyLevel OKAY|WARNING|FAILURE
Controls which notifications should be sent to syslog. The default behaviour is not to send any. Less
severe notifications always imply logging more severe notifications: Setting this to OKAY means all
notifications will be sent to syslog, setting this to WARNING will send WARNING and FAILURE
notifications but will dismiss OKAY notifications. Setting this option to FAILURE will only send
failures to syslog.

Plugin "table"
The "table plugin" provides generic means to parse tabular data and dispatch user specified values.
Values are selected based on column numbers. For example, this plugin may be used to get values from the
Linux proc(5) filesystem or CSV (comma separated values) files.

<Plugin table>
<Table "/proc/slabinfo">
Instance "slabinfo"
Separator " "
<Result>
Type gauge
InstancePrefix "active_objs"
InstancesFrom 0
ValuesFrom 1
</Result>
<Result>
Type gauge
InstancePrefix "objperslab"
InstancesFrom 0
ValuesFrom 4
</Result>
</Table>
</Plugin>

The configuration consists of one or more Table blocks, each of which configures one file to parse.
Within each Table block, there are one or more Result blocks, which configure which data to select and
how to interpret it.

The following options are available inside a Table block:

Instance instance
If specified, instance is used as the plugin instance. So, in the above example, the plugin name
"table-slabinfo" would be used. If omitted, the filename of the table is used instead, with all
special characters replaced with an underscore ("_").

Separator string
Any character of string is interpreted as a delimiter between the different columns of the table. A
sequence of two or more contiguous delimiters in the table is considered to be a single delimiter,
i. e. there cannot be any empty columns. The plugin uses the strtok_r(3) function to parse the lines
of a table - see its documentation for more details. This option is mandatory.

A horizontal tab, newline and carriage return may be specified by "\\t", "\\n" and "\\r"
respectively. Please note that the double backslashes are required because of collectd's config
parsing.

The following options are available inside a Result block:

Type type
Sets the type used to dispatch the values to the daemon. Detailed information about types and their
configuration can be found in types.db(5). This option is mandatory.

InstancePrefix prefix
If specified, prepend prefix to the type instance. If omitted, only the InstancesFrom option is
considered for the type instance.

InstancesFrom column0 [column1 ...]
If specified, the content of the given columns (identified by the column number starting at zero)
will be used to create the type instance for each row. Multiple values (and the instance prefix) will
be joined together with dashes (-) as separation character. If omitted, only the InstancePrefix
option is considered for the type instance.

The plugin itself does not check whether or not all built instances are different. ItXs your
responsibility to assure that each is unique. This is especially true, if you do not specify
InstancesFrom: You have to make sure that the table only contains one row.

If neither InstancePrefix nor InstancesFrom is given, the type instance will be empty.

ValuesFrom column0 [column1 ...]
Specifies the columns (identified by the column numbers starting at zero) whose content is used as
the actual data for the data sets that are dispatched to the daemon. How many such columns you need
is determined by the Type setting above. If you specify too many or not enough columns, the plugin
will complain about that and no data will be submitted to the daemon. The plugin uses strtoll(3) and
strtod(3) to parse counter and gauge values respectively, so anything supported by those functions is
supported by the plugin as well. This option is mandatory.

Plugin "tail"
The "tail plugin" follows logfiles, just like tail(1) does, parses each line and dispatches found values.
What is matched can be configured by the user using (extended) regular expressions, as described in
regex(7).

<Plugin "tail">
<File "/var/log/exim4/mainlog">
Instance "exim"
Interval 60
<Match>
Regex "S=([1-9][0-9]*)"
DSType "CounterAdd"
Type "ipt_bytes"
Instance "total"
</Match>
<Match>
Regex "\\<R=local_user\\>"
ExcludeRegex "\\<R=local_user\\>.*mail_spool defer"
DSType "CounterInc"
Type "counter"
Instance "local_user"
</Match>
</File>
</Plugin>

The config consists of one or more File blocks, each of which configures one logfile to parse. Within
each File block, there are one or more Match blocks, which configure a regular expression to search for.

The Instance option in the File block may be used to set the plugin instance. So in the above example the
plugin name "tail-foo" would be used. This plugin instance is for all Match blocks that follow it, until
the next Instance option. This way you can extract several plugin instances from one logfile, handy when
parsing syslog and the like.

The Interval option allows you to define the length of time between reads. If this is not set, the
default Interval will be used.

Each Match block has the following options to describe how the match should be performed:

Regex regex
Sets the regular expression to use for matching against a line. The first subexpression has to match
something that can be turned into a number by strtoll(3) or strtod(3), depending on the value of
"CounterAdd", see below. Because extended regular expressions are used, you do not need to use
backslashes for subexpressions! If in doubt, please consult regex(7). Due to collectd's config
parsing you need to escape backslashes, though. So if you want to match literal parentheses you need
to do the following:

Regex "SPAM \$Score: (-?[0-9]+\\.[0-9]+)\$"

ExcludeRegex regex
Sets an optional regular expression to use for excluding lines from the match. An example which
excludes all connections from localhost from the match:

ExcludeRegex "127\\.0\\.0\\.1"

DSType Type
Sets how the values are cumulated. Type is one of:

GaugeAverage
Calculate the average.

GaugeMin
Use the smallest number only.

GaugeMax
Use the greatest number only.

GaugeLast
Use the last number found.

CounterSet
DeriveSet
AbsoluteSet
The matched number is a counter. Simply sets the internal counter to this value. Variants exist
for "COUNTER", "DERIVE", and "ABSOLUTE" data sources.

GaugeAdd
CounterAdd
DeriveAdd
Add the matched value to the internal counter. In case of DeriveAdd, the matched number may be
negative, which will effectively subtract from the internal counter.

GaugeInc
CounterInc
DeriveInc
Increase the internal counter by one. These DSType are the only ones that do not use the matched
subexpression, but simply count the number of matched lines. Thus, you may use a regular
expression without submatch in this case.

As you'd expect the Gauge* types interpret the submatch as a floating point number, using strtod(3).
The Counter* and AbsoluteSet types interpret the submatch as an unsigned integer using strtoull(3).
The Derive* types interpret the submatch as a signed integer using strtoll(3). CounterInc and
DeriveInc do not use the submatch at all and it may be omitted in this case.

Type Type
Sets the type used to dispatch this value. Detailed information about types and their configuration
can be found in types.db(5).

Instance TypeInstance
This optional setting sets the type instance to use.

Plugin "tail_csv"
The tail_csv plugin reads files in the CSV format, e.g. the statistics file written by Snort.

Synopsis:

<Plugin "tail_csv">
<Metric "snort-dropped">
Type "percent"
Instance "dropped"
Index 1
</Metric>
<File "/var/log/snort/snort.stats">
Instance "snort-eth0"
Interval 600
Collect "snort-dropped"
</File>
</Plugin>

The configuration consists of one or more Metric blocks that define an index into the line of the CSV
file and how this value is mapped to collectd's internal representation. These are followed by one or
more Instance blocks which configure which file to read, in which interval and which metrics to extract.

<Metric Name>
The Metric block configures a new metric to be extracted from the statistics file and how it is
mapped on collectd's data model. The string Name is only used inside the Instance blocks to refer to
this block, so you can use one Metric block for multiple CSV files.

Type Type
Configures which Type to use when dispatching this metric. Types are defined in the types.db(5)
file, see the appropriate manual page for more information on specifying types. Only types with a
single data source are supported by the tail_csv plugin. The information whether the value is an
absolute value (i.e. a "GAUGE") or a rate (i.e. a "DERIVE") is taken from the Type's definition.

Instance TypeInstance
If set, TypeInstance is used to populate the type instance field of the created value lists.
Otherwise, no type instance is used.

ValueFrom Index
Configure to read the value from the field with the zero-based index Index. If the value is
parsed as signed integer, unsigned integer or double depends on the Type setting, see above.

<File Path>
Each File block represents one CSV file to read. There must be at least one File block but there can
be multiple if you have multiple CSV files.

Instance PluginInstance
Sets the plugin instance used when dispatching the values.

Collect Metric
Specifies which Metric to collect. This option must be specified at least once, and you can use
this option multiple times to specify more than one metric to be extracted from this statistic
file.

Interval Seconds
Configures the interval in which to read values from this instance / file. Defaults to the
plugin's default interval.

TimeFrom Index
Rather than using the local time when dispatching a value, read the timestamp from the field with
the zero-based index Index. The value is interpreted as seconds since epoch. The value is parsed
as a double and may be factional.

Plugin "teamspeak2"
The "teamspeak2 plugin" connects to the query port of a teamspeak2 server and polls interesting global
and virtual server data. The plugin can query only one physical server but unlimited virtual servers. You
can use the following options to configure it:

Host hostname/ip
The hostname or ip which identifies the physical server. Default: 127.0.0.1

Port port
The query port of the physical server. This needs to be a string. Default: "51234"

Server port
This option has to be added once for every virtual server the plugin should query. If you want to
query the virtual server on port 8767 this is what the option would look like:

Server "8767"

This option, although numeric, needs to be a string, i. e. you must use quotes around it! If no such
statement is given only global information will be collected.

Plugin "ted"
The TED plugin connects to a device of "The Energy Detective", a device to measure power consumption.
These devices are usually connected to a serial (RS232) or USB port. The plugin opens a configured device
and tries to read the current energy readings. For more information on TED, visit
<http://www.theenergydetective.com/>.

Available configuration options:

Device Path
Path to the device on which TED is connected. collectd will need read and write permissions on that
file.

Default: /dev/ttyUSB0

Retries Num
Apparently reading from TED is not that reliable. You can therefore configure a number of retries
here. You only configure the retries here, to if you specify zero, one reading will be performed (but
no retries if that fails); if you specify three, a maximum of four readings are performed. Negative
values are illegal.

Default: 0

Plugin "tcpconns"
The "tcpconns plugin" counts the number of currently established TCP connections based on the local port
and/or the remote port. Since there may be a lot of connections the default if to count all connections
with a local port, for which a listening socket is opened. You can use the following options to fine-tune
the ports you are interested in:

ListeningPorts true|false
If this option is set to true, statistics for all local ports for which a listening socket exists are
collected. The default depends on LocalPort and RemotePort (see below): If no port at all is
specifically selected, the default is to collect listening ports. If specific ports (no matter if
local or remote ports) are selected, this option defaults to false, i. e. only the selected ports
will be collected unless this option is set to true specifically.

LocalPort Port
Count the connections to a specific local port. This can be used to see how many connections are
handled by a specific daemon, e. g. the mailserver. You have to specify the port in numeric form, so
for the mailserver example you'd need to set 25.

RemotePort Port
Count the connections to a specific remote port. This is useful to see how much a remote service is
used. This is most useful if you want to know how many connections a local service has opened to
remote services, e. g. how many connections a mail server or news server has to other mail or news
servers, or how many connections a web proxy holds to web servers. You have to give the port in
numeric form.

AllPortsSummary true|false
If this option is set to true a summary of statistics from all connections are collectd. This option
defaults to false.

Plugin "thermal"
ForceUseProcfs true|false
By default, the Thermal plugin tries to read the statistics from the Linux "sysfs" interface. If that
is not available, the plugin falls back to the "procfs" interface. By setting this option to true,
you can force the plugin to use the latter. This option defaults to false.

Device Device
Selects the name of the thermal device that you want to collect or ignore, depending on the value of
the IgnoreSelected option. This option may be used multiple times to specify a list of devices.

IgnoreSelected true|false
Invert the selection: If set to true, all devices except the ones that match the device names
specified by the Device option are collected. By default only selected devices are collected if a
selection is made. If no selection is configured at all, all devices are selected.

Plugin "threshold"
The Threshold plugin checks values collected or received by collectd against a configurable threshold and
issues notifications if values are out of bounds.

Documentation for this plugin is available in the collectd-threshold(5) manual page.

Plugin "tokyotyrant"
The TokyoTyrant plugin connects to a TokyoTyrant server and collects a couple metrics: number of records,
and database size on disk.

Host Hostname/IP
The hostname or ip which identifies the server. Default: 127.0.0.1

Port Service/Port
The query port of the server. This needs to be a string, even if the port is given in its numeric
form. Default: 1978

Plugin "turbostat"
The Turbostat plugin reads CPU frequency and C-state residency on modern Intel processors by using the
new Model Specific Registers.

CoreCstates Bitmask(Integer)
Bitmask of the list of core C states supported by the processor. This option should only be used if
the automated detection fails. Default value extracted from the cpu model and family.

Currently supported C-states (by this plugin): 3, 6, 7

Example: (1<<3)+(1<<6)+(1<<7) = 392 for all states

PackageCstates Bitmask(Integer)
Bitmask of the list of pacages C states supported by the processor. This option should only be used
if the automated detection fails. Default value extracted from the cpu model and family.

Currently supported C-states (by this plugin): 2, 3, 6, 7, 8, 9, 10

Example: (1<<2)+(1<<3)+(1<<6)+(1<<7) = 396 for states 2, 3, 6 and 7

SystemManagementInterrupt true|false
Boolean enabling the collection of the I/O System-Management Interrupt counter'. This option should
only be used if the automated detection fails or if you want to disable this feature.

DigitalTemperatureSensor true|false
Boolean enabling the collection of the temperature of each core. This option should only be used if
the automated detectionfails or if you want to disable this feature.

DigitalTemperatureSensor true|false
Boolean enabling the collection of the temperature of each package. This option should only be used
if the automated detectionfails or if you want to disable this feature.

TCCActivationTemp Temperature
Thermal Control Circuit Activation Temperature of the installed CPU. This temperature is used when
collecting the temperature of cores or packages. This option should only be used if the automated
detection fails. Default value extracted from MSR_IA32_TEMPERATURE_TARGET

RunningAveragePowerLimit Bitmask(Integer)
Bitmask of the list of elements to be thermally monitored. This option should only be used if the
automated detection fails or if you want to disable some collections. The different bits of this
bitmask accepted by this plugin are:

0 ('1'): Package
1 ('2'): DRAM
2 ('4'): Cores
3 ('8'): Embedded graphic device

Plugin "unixsock"
SocketFile Path
Sets the socket-file which is to be created.

SocketGroup Group
If running as root change the group of the UNIX-socket after it has been created. Defaults to
collectd.

DeleteSocket false|true
If set to true, delete the socket file before calling bind(2), if a file with the given name already
exists. If collectd crashes a socket file may be left over, preventing the daemon from opening a new
socket when restarted. Since this is potentially dangerous, this defaults to false.

Plugin "uuid"
This plugin, if loaded, causes the Hostname to be taken from the machine's UUID. The UUID is a
universally unique designation for the machine, usually taken from the machine's BIOS. This is most
useful if the machine is running in a virtual environment such as Xen, in which case the UUID is
preserved across shutdowns and migration.

The following methods are used to find the machine's UUID, in order:

• Check /etc/uuid (or UUIDFile).

• Check for UUID from HAL (<http://www.freedesktop.org/wiki/Software/hal>) if present.

• Check for UUID from "dmidecode" / SMBIOS.

• Check for UUID from Xen hypervisor.

If no UUID can be found then the hostname is not modified.

UUIDFile Path
Take the UUID from the given file (default /etc/uuid).

Plugin "varnish"
The varnish plugin collects information about Varnish, an HTTP accelerator. It collects a subset of the
values displayed by varnishstat(1), and organizes them in categories which can be enabled or disabled.
Currently only metrics shown in varnishstat(1)'s MAIN section are collected. The exact meaning of each
metric can be found in varnish-counters(7).

Synopsis:

<Plugin "varnish">
<Instance "example">
CollectBackend true
CollectBan false
CollectCache true
CollectConnections true
CollectDirectorDNS false
CollectESI false
CollectFetch false
CollectHCB false
CollectObjects false
CollectPurge false
CollectSession false
CollectSHM true
CollectSMA false
CollectSMS false
CollectSM false
CollectStruct false
CollectTotals false
CollectUptime false
CollectVCL false
CollectVSM false
CollectWorkers false
</Instance>
</Plugin>

The configuration consists of one or more <Instance Name> blocks. Name is the parameter passed to
"varnishd -n". If left empty, it will collectd statistics from the default "varnishd" instance (this
should work fine in most cases).

Inside each <Instance> blocks, the following options are recognized:

CollectBackend true|false
Back-end connection statistics, such as successful, reused, and closed connections. True by default.

CollectBan true|false
Statistics about ban operations, such as number of bans added, retired, and number of objects tested
against ban operations. Only available with Varnish 3.x and above. False by default.

CollectCache true|false
Cache hits and misses. True by default.

CollectConnections true|false
Number of client connections received, accepted and dropped. True by default.

CollectDirectorDNS true|false
DNS director lookup cache statistics. Only available with Varnish 3.x. False by default.

CollectESI true|false
Edge Side Includes (ESI) parse statistics. False by default.

CollectFetch true|false
Statistics about fetches (HTTP requests sent to the backend). False by default.

CollectHCB true|false
Inserts and look-ups in the crit bit tree based hash. Look-ups are divided into locked and unlocked
look-ups. False by default.

CollectObjects true|false
Statistics on cached objects: number of objects expired, nuked (prematurely expired), saved, moved,
etc. False by default.

CollectPurge true|false
Statistics about purge operations, such as number of purges added, retired, and number of objects
tested against purge operations. Only available with Varnish 2.x. False by default.

CollectSession true|false
Client session statistics. Number of past and current sessions, session herd and linger counters,
etc. False by default. Note that if using Varnish 4.x, some metrics found in the Connections and
Threads sections with previous versions of Varnish have been moved here.

CollectSHM true|false
Statistics about the shared memory log, a memory region to store log messages which is flushed to
disk when full. True by default.

CollectSMA true|false
malloc or umem (umem_alloc(3MALLOC) based) storage statistics. The umem storage component is Solaris
specific. Only available with Varnish 2.x. False by default.

CollectSMS true|false
synth (synthetic content) storage statistics. This storage component is used internally only. False
by default.

CollectSM true|false
file (memory mapped file) storage statistics. Only available with Varnish 2.x. False by default.

CollectStruct true|false
Current varnish internal state statistics. Number of current sessions, objects in cache store, open
connections to backends (with Varnish 2.x), etc. False by default.

CollectTotals true|false
Collects overview counters, such as the number of sessions created, the number of requests and bytes
transferred. False by default.

CollectUptime true|false
Varnish uptime. Only available with Varnish 3.x and above. False by default.

CollectVCL true|false
Number of total (available + discarded) VCL (config files). False by default.

CollectVSM true|false
Collect statistics about Varnish's shared memory usage (used by the logging and statistics
subsystems). Only available with Varnish 4.x. False by default.

CollectWorkers true|false
Collect statistics about worker threads. False by default.

Plugin "virt"
This plugin allows CPU, disk and network load to be collected for virtualized guests on the machine. This
means that these metrics can be collected for guest systems without installing any software on them -
collectd only runs on the host system. The statistics are collected through libvirt
(<http://libvirt.org/>).

Only Connection is required.

Connection uri
Connect to the hypervisor given by uri. For example if using Xen use:

Connection "xen:///"

Details which URIs allowed are given at <http://libvirt.org/uri.html>.

RefreshInterval seconds
Refresh the list of domains and devices every seconds. The default is 60 seconds. Setting this to be
the same or smaller than the Interval will cause the list of domains and devices to be refreshed on
every iteration.

Refreshing the devices in particular is quite a costly operation, so if your virtualization setup is
static you might consider increasing this. If this option is set to 0, refreshing is disabled
completely.

Domain name
BlockDevice name:dev
InterfaceDevice name:dev
IgnoreSelected true|false
Select which domains and devices are collected.

If IgnoreSelected is not given or false then only the listed domains and disk/network devices are
collected.

If IgnoreSelected is true then the test is reversed and the listed domains and disk/network devices
are ignored, while the rest are collected.

The domain name and device names may use a regular expression, if the name is surrounded by /.../ and
collectd was compiled with support for regexps.

The default is to collect statistics for all domains and all their devices.

Example:

BlockDevice "/:hdb/"
IgnoreSelected "true"

Ignore all hdb devices on any domain, but other block devices (eg. hda) will be collected.

HostnameFormat name|uuid|hostname|...
When the virt plugin logs data, it sets the hostname of the collected data according to this setting.
The default is to use the guest name as provided by the hypervisor, which is equal to setting name.

uuid means use the guest's UUID. This is useful if you want to track the same guest across
migrations.

hostname means to use the global Hostname setting, which is probably not useful on its own because
all guests will appear to have the same name.

You can also specify combinations of these fields. For example name uuid means to concatenate the
guest name and UUID (with a literal colon character between, thus "foo:1234-1234-1234-1234").

At the moment of writing (collectd-5.5), hostname string is limited to 62 characters. In case when
combination of fields exceeds 62 characters, hostname will be truncated without a warning.

InterfaceFormat name|address
When the virt plugin logs interface data, it sets the name of the collected data according to this
setting. The default is to use the path as provided by the hypervisor (the "dev" property of the
target node), which is equal to setting name.

address means use the interface's mac address. This is useful since the interface path might change
between reboots of a guest or across migrations.

PluginInstanceFormat name|uuid
When the virt plugin logs data, it sets the plugin_instance of the collected data according to this
setting. The default is to use the guest name as provided by the hypervisor, which is equal to
setting name.

uuid means use the guest's UUID.

You can also specify combinations of these fields. For example name uuid means to concatenate the
guest name and UUID (with a literal colon character between, thus "foo:1234-1234-1234-1234").

Plugin "vmem"
The "vmem" plugin collects information about the usage of virtual memory. Since the statistics provided
by the Linux kernel are very detailed, they are collected very detailed. However, to get all the details,
you have to switch them on manually. Most people just want an overview over, such as the number of pages
read from swap space.

Verbose true|false
Enables verbose collection of information. This will start collecting page "actions", e. g. page
allocations, (de)activations, steals and so on. Part of these statistics are collected on a "per
zone" basis.

Plugin "vserver"
This plugin doesn't have any options. VServer support is only available for Linux. It cannot yet be found
in a vanilla kernel, though. To make use of this plugin you need a kernel that has VServer support built
in, i. e. you need to apply the patches and compile your own kernel, which will then provide the
/proc/virtual filesystem that is required by this plugin.

The VServer homepage can be found at <http://linux-vserver.org/>.

Note: The traffic collected by this plugin accounts for the amount of traffic passing a socket which
might be a lot less than the actual on-wire traffic (e. g. due to headers and retransmission). If you
want to collect on-wire traffic you could, for example, use the logging facilities of iptables to feed
data for the guest IPs into the iptables plugin.

Plugin "write_graphite"
The "write_graphite" plugin writes data to Graphite, an open-source metrics storage and graphing project.
The plugin connects to Carbon, the data layer of Graphite, via TCP or UDP and sends data via the "line
based" protocol (per default using port 2003). The data will be sent in blocks of at most 1428 bytes to
minimize the number of network packets.

Synopsis:

<Plugin write_graphite>
<Node "example">
Host "localhost"
Port "2003"
Protocol "tcp"
LogSendErrors true
Prefix "collectd"
</Node>
</Plugin>

The configuration consists of one or more <Node Name> blocks. Inside the Node blocks, the following
options are recognized:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 2003.

Protocol String
Protocol to use when connecting to Graphite. Defaults to "tcp".

LogSendErrors false|true
If set to true (the default), logs errors when sending data to Graphite. If set to false, it will
not log the errors. This is especially useful when using Protocol UDP since many times we want to use
the "fire-and-forget" approach and logging errors fills syslog with unneeded messages.

Prefix String
When set, String is added in front of the host name. Dots and whitespace are not escaped in this
string (see EscapeCharacter below).

Postfix String
When set, String is appended to the host name. Dots and whitespace are not escaped in this string
(see EscapeCharacter below).

EscapeCharacter Char
Carbon uses the dot (".") as escape character and doesn't allow whitespace in the identifier. The
EscapeCharacter option determines which character dots, whitespace and control characters are
replaced with. Defaults to underscore ("_").

StoreRates false|true
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i. e. as an increasing integer number.

SeparateInstances false|true
If set to true, the plugin instance and type instance will be in their own path component, for
example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and
likewise the type and type instance) are put into one component, for example "host.cpu-0.cpu-idle".

AlwaysAppendDS false|true
If set to true, append the name of the Data Source (DS) to the "metric" identifier. If set to false
(the default), this is only done when there is more than one DS.

Plugin "write_tsdb"
The "write_tsdb" plugin writes data to OpenTSDB, a scalable open-source time series database. The plugin
connects to a TSD, a masterless, no shared state daemon that ingests metrics and stores them in HBase.
The plugin uses TCP over the "line based" protocol with a default port 4242. The data will be sent in
blocks of at most 1428 bytes to minimize the number of network packets.

Synopsis:

<Plugin write_tsdb>
<Node "example">
Host "tsd-1.my.domain"
Port "4242"
HostTags "status=production"
</Node>
</Plugin>

The configuration consists of one or more <Node Name> blocks. Inside the Node blocks, the following
options are recognized:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 4242.

HostTags String
When set, HostTags is added to the end of the metric. It is intended to be used for name=value pairs
that the TSD will tag the metric with. Dots and whitespace are not escaped in this string.

StoreRates false|true
If set to true, convert counter values to rates. If set to false (the default) counter values are
stored as is, as an increasing integer number.

AlwaysAppendDS false|true
If set the true, append the name of the Data Source (DS) to the "metric" identifier. If set to false
(the default), this is only done when there is more than one DS.

Plugin "write_mongodb"
The write_mongodb plugin will send values to MongoDB, a schema-less NoSQL database.

Synopsis:

<Plugin "write_mongodb">
<Node "default">
Host "localhost"
Port "27017"
Timeout 1000
StoreRates true
</Node>
</Plugin>

The plugin can send values to multiple instances of MongoDB by specifying one Node block for each
instance. Within the Node blocks, the following options are available:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 27017.

Timeout Milliseconds
Set the timeout for each operation on MongoDB to Timeout milliseconds. Setting this option to zero
means no timeout, which is the default.

StoreRates false|true
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i.e. as an increasing integer number.

Database Database
User User
Password Password
Sets the information used when authenticating to a MongoDB database. The fields are optional (in
which case no authentication is attempted), but if you want to use authentication all three fields
must be set.

Plugin "write_http"
This output plugin submits values to an HTTP server using POST requests and encoding metrics with JSON or
using the "PUTVAL" command described in collectd-unixsock(5).

Synopsis:

<Plugin "write_http">
<Node "example">
URL "http://example.com/post-collectd"
User "collectd"
Password "weCh3ik0"
Format JSON
</Node>
</Plugin>

The plugin can send values to multiple HTTP servers by specifying one <Node Name> block for each server.
Within each Node block, the following options are available:

URL URL
URL to which the values are submitted to. Mandatory.

User Username
Optional user name needed for authentication.

Password Password
Optional password needed for authentication.

VerifyPeer true|false
Enable or disable peer SSL certificate verification. See <http://curl.haxx.se/docs/sslcerts.html> for
details. Enabled by default.

CAPath Directory
Directory holding one or more CA certificate files. You can use this if for some reason all the
needed CA certificates aren't in the same file and can't be pointed to using the CACert option.
Requires "libcurl" to be built against OpenSSL.

ClientKey File
File that holds the private key in PEM format to be used for certificate-based authentication.

ClientCert File
File that holds the SSL certificate to be used for certificate-based authentication.

ClientKeyPass Password
Password required to load the private key in ClientKey.

Format Command|JSON
Format of the output to generate. If set to Command, will create output that is understood by the
Exec and UnixSock plugins. When set to JSON, will create output in the JavaScript Object Notation
(JSON).

Defaults to Command.

StoreRates true|false
If set to true, convert counter values to rates. If set to false (the default) counter values are
stored as is, i.e. as an increasing integer number.

BufferSize Bytes
Sets the send buffer size to Bytes. By increasing this buffer, less HTTP requests will be generated,
but more metrics will be batched / metrics are cached for longer before being sent, introducing
additional delay until they are available on the server side. Bytes must be at least 1024 and cannot
exceed the size of an "int", i.e. 2 GByte. Defaults to 4096.

LowSpeedLimit Bytes per Second
Sets the minimal transfer rate in Bytes per Second below which the connection with the HTTP server
will be considered too slow and aborted. All the data submitted over this connection will probably be
lost. Defaults to 0, which means no minimum transfer rate is enforced.

Timeout Timeout
Sets the maximum time in milliseconds given for HTTP POST operations to complete. When this limit is
reached, the POST operation will be aborted, and all the data in the current send buffer will
probably be lost. Defaults to 0, which means the connection never times out.

The "write_http" plugin regularly submits the collected values to the HTTP server. How frequently
this happens depends on how much data you are collecting and the size of BufferSize. The optimal
value to set Timeout to is slightly below this interval, which you can estimate by monitoring the
network traffic between collectd and the HTTP server.

Plugin "write_kafka"
The write_kafka plugin will send values to a Kafka topic, a distributed queue. Synopsis:

<Plugin "write_kafka">
Property "metadata.broker.list" "broker1:9092,broker2:9092"
<Topic "collectd">
Format JSON
</Topic>
</Plugin>

The following options are understood by the write_kafka plugin:

<Topic Name>
The plugin's configuration consists of one or more Topic blocks. Each block is given a unique Name
and specifies one kafka producer. Inside the Topic block, the following per-topic options are
understood:

Property String String
Configure the named property for the current topic. Properties are forwarded to the kafka
producer library librdkafka.

Key String
Use the specified string as a partioning key for the topic. Kafka breaks topic into partitions
and guarantees that for a given topology, the same consumer will be used for a specific key. The
special (case insensitive) string Random can be used to specify that an arbitrary partition
should be used.

Format Command|JSON|Graphite
Selects the format in which messages are sent to the broker. If set to Command (the default),
values are sent as "PUTVAL" commands which are identical to the syntax used by the Exec and
UnixSock plugins.

If set to JSON, the values are encoded in the JavaScript Object Notation, an easy and straight
forward exchange format.

If set to Graphite, values are encoded in the Graphite format, which is "<metric> <value>
<timestamp>\n".

StoreRates true|false
Determines whether or not "COUNTER", "DERIVE" and "ABSOLUTE" data sources are converted to a rate
(i.e. a "GAUGE" value). If set to false (the default), no conversion is performed. Otherwise the
conversion is performed using the internal value cache.

Please note that currently this option is only used if the Format option has been set to JSON.

GraphitePrefix (Format=Graphite only)
A prefix can be added in the metric name when outputting in the Graphite format. It's added
before the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphitePostfix (Format=Graphite only)
A postfix can be added in the metric name when outputting in the Graphite format. It's added
after the Host name. Metric name will be "<prefix><host><postfix><plugin><type><name>"

GraphiteEscapeChar (Format=Graphite only)
Specify a character to replace dots (.) in the host part of the metric name. In Graphite metric
name, dots are used as separators between different metric parts (host, plugin, type). Default
is "_" (Underscore).

GraphiteSeparateInstances false|true
If set to true, the plugin instance and type instance will be in their own path component, for
example "host.cpu.0.cpu.idle". If set to false (the default), the plugin and plugin instance (and
likewise the type and type instance) are put into one component, for example
"host.cpu-0.cpu-idle".

StoreRates true|false
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i.e. as an increasing integer number.

This will be reflected in the "ds_type" tag: If StoreRates is enabled, converted values will have
"rate" appended to the data source type, e.g. "ds_type:derive:rate".

Property String String
Configure the kafka producer through properties, you almost always will want to set
metadata.broker.list to your Kafka broker list.

Plugin "write_redis"
The write_redis plugin submits values to Redis, a data structure server.

Synopsis:

<Plugin "write_redis">
<Node "example">
Host "localhost"
Port "6379"
Timeout 1000
</Node>
</Plugin>

Values are submitted to Sorted Sets, using the metric name as the key, and the timestamp as the score.
Retrieving a date range can then be done using the "ZRANGEBYSCORE" Redis command. Additionally, all the
identifiers of these Sorted Sets are kept in a Set called "collectd/values" and can be retrieved using
the "SMEMBERS" Redis command. See <http://redis.io/commands#sorted_set> and
<http://redis.io/commands#set> for details.

The information shown in the synopsis above is the default configuration which is used by the plugin if
no configuration is present.

The plugin can send values to multiple instances of Redis by specifying one Node block for each instance.
Within the Node blocks, the following options are available:

Node Nodename
The Node block identifies a new Redis node, that is a new Redis instance running on a specified host
and port. The node name is a canonical identifier which is used as plugin instance. It is limited to
51 characters in length.

Host Hostname
The Host option is the hostname or IP-address where the Redis instance is running on.

Timeout Milliseconds
The Timeout option sets the socket connection timeout, in milliseconds.

Plugin "write_riemann"
The write_riemann plugin will send values to Riemann, a powerful stream aggregation and monitoring
system. The plugin sends Protobuf encoded data to Riemann using UDP packets.

Synopsis:

<Plugin "write_riemann">
<Node "example">
Host "localhost"
Port "5555"
Protocol UDP
StoreRates true
AlwaysAppendDS false
TTLFactor 2.0
</Node>
Tag "foobar"
Attribute "foo" "bar"
</Plugin>

The following options are understood by the write_riemann plugin:

<Node Name>
The plugin's configuration consists of one or more Node blocks. Each block is given a unique Name and
specifies one connection to an instance of Riemann. Indise the Node block, the following per-
connection options are understood:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 5555.

Protocol UDP|TCP
Specify the protocol to use when communicating with Riemann. Defaults to TCP.

Batch true|false
If set to true and Protocol is set to TCP, events will be batched in memory and flushed at
regular intervals or when BatchMaxSize is exceeded.

Notifications are not batched and sent as soon as possible.

When enabled, it can occur that events get processed by the Riemann server close to or after
their expiration time. Tune the TTLFactor and BatchMaxSize settings according to the amount of
values collected, if this is an issue.

Defaults to true

BatchMaxSize size
Maximum payload size for a riemann packet. Defaults to 8192

StoreRates true|false
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i.e. as an increasing integer number.

This will be reflected in the "ds_type" tag: If StoreRates is enabled, converted values will have
"rate" appended to the data source type, e.g. "ds_type:derive:rate".

AlwaysAppendDS false|true
If set to true, append the name of the Data Source (DS) to the "service", i.e. the field that,
together with the "host" field, uniquely identifies a metric in Riemann. If set to false (the
default), this is only done when there is more than one DS.

TTLFactor Factor
Riemann events have a Time to Live (TTL) which specifies how long each event is considered
active. collectd populates this field based on the metrics interval setting. This setting
controls the factor with which the interval is multiplied to set the TTL. The default value is
2.0. Unless you know exactly what you're doing, you should only increase this setting from its
default value.

Notifications false|true
If set to true, create riemann events for notifications. This is true by default. When processing
thresholds from write_riemann, it might prove useful to avoid getting notification events.

CheckThresholds false|true
If set to true, attach state to events based on thresholds defined in the Threshold plugin.
Defaults to false.

EventServicePrefix String
Add the given string as a prefix to the event service name. If EventServicePrefix not set or set
to an empty string (""), no prefix will be used.

Tag String
Add the given string as an additional tag to the metric being sent to Riemann.

Attribute String String
Consider the two given strings to be the key and value of an additional attribute for each metric
being sent out to Riemann.

Plugin "write_sensu"
The write_sensu plugin will send values to Sensu, a powerful stream aggregation and monitoring system.
The plugin sends JSON encoded data to a local Sensu client using a TCP socket.

At the moment, the write_sensu plugin does not send over a collectd_host parameter so it is not possible
to use one collectd instance as a gateway for others. Each collectd host must pair with one Sensu client.

Synopsis:

<Plugin "write_sensu">
<Node "example">
Host "localhost"
Port "3030"
StoreRates true
AlwaysAppendDS false
MetricHandler "influx"
MetricHandler "default"
NotificationHandler "flapjack"
NotificationHandler "howling_monkey"
Notifications true
</Node>
Tag "foobar"
Attribute "foo" "bar"
</Plugin>

The following options are understood by the write_sensu plugin:

<Node Name>
The plugin's configuration consists of one or more Node blocks. Each block is given a unique Name and
specifies one connection to an instance of Sensu. Inside the Node block, the following per-connection
options are understood:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 3030.

StoreRates true|false
If set to true (the default), convert counter values to rates. If set to false counter values are
stored as is, i.e. as an increasing integer number.

This will be reflected in the "collectd_data_source_type" tag: If StoreRates is enabled,
converted values will have "rate" appended to the data source type, e.g.
"collectd_data_source_type:derive:rate".

AlwaysAppendDS false|true
If set the true, append the name of the Data Source (DS) to the "service", i.e. the field that,
together with the "host" field, uniquely identifies a metric in Sensu. If set to false (the
default), this is only done when there is more than one DS.

Notifications false|true
If set to true, create Sensu events for notifications. This is false by default. At least one of
Notifications or Metrics should be enabled.

Metrics false|true
If set to true, create Sensu events for metrics. This is false by default. At least one of
Notifications or Metrics should be enabled.

Separator String
Sets the separator for Sensu metrics name or checks. Defaults to "/".

MetricHandler String
Add a handler that will be set when metrics are sent to Sensu. You can add several of them, one
per line. Defaults to no handler.

NotificationHandler String
Add a handler that will be set when notifications are sent to Sensu. You can add several of them,
one per line. Defaults to no handler.

EventServicePrefix String
Add the given string as a prefix to the event service name. If EventServicePrefix not set or set
to an empty string (""), no prefix will be used.

Tag String
Add the given string as an additional tag to the metric being sent to Sensu.

Attribute String String
Consider the two given strings to be the key and value of an additional attribute for each metric
being sent out to Sensu.

Plugin "zookeeper"
The zookeeper plugin will collect statistics from a Zookeeper server using the mntr command. It requires
Zookeeper 3.4.0+ and access to the client port.

Synopsis:

Host Address
Hostname or address to connect to. Defaults to "localhost".

Port Service
Service name or port number to connect to. Defaults to 2181.

THRESHOLD CONFIGURATION

Starting with version 4.3.0 collectd has support for monitoring. By that we mean that the values are not
only stored or sent somewhere, but that they are judged and, if a problem is recognized, acted upon. The
only action collectd takes itself is to generate and dispatch a "notification". Plugins can register to
receive notifications and perform appropriate further actions.

Since systems and what you expect them to do differ a lot, you can configure thresholds for your values
freely. This gives you a lot of flexibility but also a lot of responsibility.

Every time a value is out of range a notification is dispatched. This means that the idle percentage of
your CPU needs to be less then the configured threshold only once for a notification to be generated.
There's no such thing as a moving average or similar - at least not now.

Also, all values that match a threshold are considered to be relevant or "interesting". As a consequence
collectd will issue a notification if they are not received for Timeout iterations. The Timeout
configuration option is explained in section "GLOBAL OPTIONS". If, for example, Timeout is set to "2"
(the default) and some hosts sends it's CPU statistics to the server every 60 seconds, a notification
will be dispatched after about 120 seconds. It may take a little longer because the timeout is checked
only once each Interval on the server.

When a value comes within range again or is received after it was missing, an "OKAY-notification" is
dispatched.

Here is a configuration example to get you started. Read below for more information.

<Plugin threshold>
<Type "foo">
WarningMin 0.00
WarningMax 1000.00
FailureMin 0.00
FailureMax 1200.00
Invert false
Instance "bar"
</Type>

<Plugin "interface">
Instance "eth0"
<Type "if_octets">
FailureMax 10000000
DataSource "rx"
</Type>
</Plugin>

<Host "hostname">
<Type "cpu">
Instance "idle"
FailureMin 10
</Type>

<Plugin "memory">
<Type "memory">
Instance "cached"
WarningMin 100000000
</Type>
</Plugin>
</Host>
</Plugin>

There are basically two types of configuration statements: The "Host", "Plugin", and "Type" blocks select
the value for which a threshold should be configured. The "Plugin" and "Type" blocks may be specified
further using the "Instance" option. You can combine the block by nesting the blocks, though they must be
nested in the above order, i. e. "Host" may contain either "Plugin" and "Type" blocks, "Plugin" may only
contain "Type" blocks and "Type" may not contain other blocks. If multiple blocks apply to the same value
the most specific block is used.

The other statements specify the threshold to configure. They must be included in a "Type" block.
Currently the following statements are recognized:

FailureMax Value
WarningMax Value
Sets the upper bound of acceptable values. If unset defaults to positive infinity. If a value is
greater than FailureMax a FAILURE notification will be created. If the value is greater than
WarningMax but less than (or equal to) FailureMax a WARNING notification will be created.

FailureMin Value
WarningMin Value
Sets the lower bound of acceptable values. If unset defaults to negative infinity. If a value is less
than FailureMin a FAILURE notification will be created. If the value is less than WarningMin but
greater than (or equal to) FailureMin a WARNING notification will be created.

DataSource DSName
Some data sets have more than one "data source". Interesting examples are the "if_octets" data set,
which has received ("rx") and sent ("tx") bytes and the "disk_ops" data set, which holds "read" and
"write" operations. The system load data set, "load", even has three data sources: "shortterm",
"midterm", and "longterm".

Normally, all data sources are checked against a configured threshold. If this is undesirable, or if
you want to specify different limits for each data source, you can use the DataSource option to have
a threshold apply only to one data source.

Invert true|false
If set to true the range of acceptable values is inverted, i. e. values between FailureMin and
FailureMax (WarningMin and WarningMax) are not okay. Defaults to false.

Persist true|false
Sets how often notifications are generated. If set to true one notification will be generated for
each value that is out of the acceptable range. If set to false (the default) then a notification is
only generated if a value is out of range but the previous value was okay.

This applies to missing values, too: If set to true a notification about a missing value is generated
once every Interval seconds. If set to false only one such notification is generated until the value
appears again.

Percentage true|false
If set to true, the minimum and maximum values given are interpreted as percentage value, relative to
the other data sources. This is helpful for example for the "df" type, where you may want to issue a
warning when less than 5 % of the total space is available. Defaults to false.

Hits Number
Delay creating the notification until the threshold has been passed Number times. When a notification
has been generated, or when a subsequent value is inside the threshold, the counter is reset. If, for
example, a value is collected once every 10 seconds and Hits is set to 3, a notification will be
dispatched at most once every 30 seconds.

This is useful when short bursts are not a problem. If, for example, 100% CPU usage for up to a
minute is normal (and data is collected every 10 seconds), you could set Hits to 6 to account for
this.

Hysteresis Number
When set to non-zero, a hysteresis value is applied when checking minimum and maximum bounds. This is
useful for values that increase slowly and fluctuate a bit while doing so. When these values come
close to the threshold, they may "flap", i.e. switch between failure / warning case and okay case
repeatedly.

If, for example, the threshold is configures as

WarningMax 100.0
Hysteresis 1.0

then a Warning notification is created when the value exceeds 101 and the corresponding Okay
notification is only created once the value falls below 99, thus avoiding the "flapping".

FILTER CONFIGURATION

Starting with collectd 4.6 there is a powerful filtering infrastructure implemented in the daemon. The
concept has mostly been copied from ip_tables, the packet filter infrastructure for Linux. We'll use a
similar terminology, so that users that are familiar with iptables feel right at home.

Terminology
The following are the terms used in the remainder of the filter configuration documentation. For an
ASCII-art schema of the mechanism, see "General structure" below.

Match
A match is a criteria to select specific values. Examples are, of course, the name of the value or
it's current value.

Matches are implemented in plugins which you have to load prior to using the match. The name of such
plugins starts with the "match_" prefix.

Target
A target is some action that is to be performed with data. Such actions could, for example, be to
change part of the value's identifier or to ignore the value completely.

Some of these targets are built into the daemon, see "Built-in targets" below. Other targets are
implemented in plugins which you have to load prior to using the target. The name of such plugins
starts with the "target_" prefix.

Rule
The combination of any number of matches and at least one target is called a rule. The target actions
will be performed for all values for which all matches apply. If the rule does not have any matches
associated with it, the target action will be performed for all values.

Chain
A chain is a list of rules and possibly default targets. The rules are tried in order and if one
matches, the associated target will be called. If a value is handled by a rule, it depends on the
target whether or not any subsequent rules are considered or if traversal of the chain is aborted,
see "Flow control" below. After all rules have been checked, the default targets will be executed.

General structure
The following shows the resulting structure:

+---------+
! Chain !
+---------+
!
V
+---------+ +---------+ +---------+ +---------+
! Rule !->! Match !->! Match !->! Target !
+---------+ +---------+ +---------+ +---------+
!
V
+---------+ +---------+ +---------+
! Rule !->! Target !->! Target !
+---------+ +---------+ +---------+
!
V
:
:
!
V
+---------+ +---------+ +---------+
! Rule !->! Match !->! Target !
+---------+ +---------+ +---------+
!
V
+---------+
! Default !
! Target !
+---------+

Flow control
There are four ways to control which way a value takes through the filter mechanism:

jump
The built-in jump target can be used to "call" another chain, i. e. process the value with another
chain. When the called chain finishes, usually the next target or rule after the jump is executed.

stop
The stop condition, signaled for example by the built-in target stop, causes all processing of the
value to be stopped immediately.

return
Causes processing in the current chain to be aborted, but processing of the value generally will
continue. This means that if the chain was called via Jump, the next target or rule after the jump
will be executed. If the chain was not called by another chain, control will be returned to the
daemon and it may pass the value to another chain.

continue
Most targets will signal the continue condition, meaning that processing should continue normally.
There is no special built-in target for this condition.

Synopsis
The configuration reflects this structure directly:

PostCacheChain "PostCache"
<Chain "PostCache">
<Rule "ignore_mysql_show">
<Match "regex">
Plugin "^mysql$"
Type "^mysql_command$"
TypeInstance "^show_"
</Match>
<Target "stop">
</Target>
</Rule>
<Target "write">
Plugin "rrdtool"
</Target>
</Chain>

The above configuration example will ignore all values where the plugin field is "mysql", the type is
"mysql_command" and the type instance begins with "show_". All other values will be sent to the "rrdtool"
write plugin via the default target of the chain. Since this chain is run after the value has been added
to the cache, the MySQL "show_*" command statistics will be available via the "unixsock" plugin.

List of configuration options
PreCacheChain ChainName
PostCacheChain ChainName
Configure the name of the "pre-cache chain" and the "post-cache chain". The argument is the name of a
chain that should be executed before and/or after the values have been added to the cache.

To understand the implications, it's important you know what is going on inside collectd. The
following diagram shows how values are passed from the read-plugins to the write-plugins:

+---------------+
! Read-Plugin !
+-------+-------+
!
+ - - - - V - - - - +
: +---------------+ :
: ! Pre-Cache ! :
: ! Chain ! :
: +-------+-------+ :
: ! :
: V :
: +-------+-------+ : +---------------+
: ! Cache !--->! Value Cache !
: ! insert ! : +---+---+-------+
: +-------+-------+ : ! !
: ! ,------------' !
: V V : V
: +-------+---+---+ : +-------+-------+
: ! Post-Cache +--->! Write-Plugins !
: ! Chain ! : +---------------+
: +---------------+ :
: :
: dispatch values :
+ - - - - - - - - - +

After the values are passed from the "read" plugins to the dispatch functions, the pre-cache chain is
run first. The values are added to the internal cache afterwards. The post-cache chain is run after
the values have been added to the cache. So why is it such a huge deal if chains are run before or
after the values have been added to this cache?

Targets that change the identifier of a value list should be executed before the values are added to
the cache, so that the name in the cache matches the name that is used in the "write" plugins. The
"unixsock" plugin, too, uses this cache to receive a list of all available values. If you change the
identifier after the value list has been added to the cache, this may easily lead to confusion, but
it's not forbidden of course.

The cache is also used to convert counter values to rates. These rates are, for example, used by the
"value" match (see below). If you use the rate stored in the cache before the new value is added, you
will use the old, previous rate. Write plugins may use this rate, too, see the "csv" plugin, for
example. The "unixsock" plugin uses these rates too, to implement the "GETVAL" command.

Last but not last, the stop target makes a difference: If the pre-cache chain returns the stop
condition, the value will not be added to the cache and the post-cache chain will not be run.

Chain Name
Adds a new chain with a certain name. This name can be used to refer to a specific chain, for example
to jump to it.

Within the Chain block, there can be Rule blocks and Target blocks.

Rule [Name]
Adds a new rule to the current chain. The name of the rule is optional and currently has no meaning
for the daemon.

Within the Rule block, there may be any number of Match blocks and there must be at least one Target
block.

Match Name
Adds a match to a Rule block. The name specifies what kind of match should be performed. Available
matches depend on the plugins that have been loaded.

The arguments inside the Match block are passed to the plugin implementing the match, so which
arguments are valid here depends on the plugin being used. If you do not need any to pass any
arguments to a match, you can use the shorter syntax:

Match "foobar"

Which is equivalent to:

Target Name
Add a target to a rule or a default target to a chain. The name specifies what kind of target is to
be added. Which targets are available depends on the plugins being loaded.

The arguments inside the Target block are passed to the plugin implementing the target, so which
arguments are valid here depends on the plugin being used. If you do not need any to pass any
arguments to a target, you can use the shorter syntax:

Target "stop"

This is the same as writing:

Built-in targets
The following targets are built into the core daemon and therefore need no plugins to be loaded:

return
Signals the "return" condition, see the "Flow control" section above. This causes the current chain
to stop processing the value and returns control to the calling chain. The calling chain will
continue processing targets and rules just after the jump target (see below). This is very similar to
the RETURN target of iptables, see iptables(8).

This target does not have any options.

Example:

Target "return"

stop
Signals the "stop" condition, see the "Flow control" section above. This causes processing of the
value to be aborted immediately. This is similar to the DROP target of iptables, see iptables(8).

This target does not have any options.

Example:

Target "stop"

write
Sends the value to "write" plugins.

Available options:

Plugin Name
Name of the write plugin to which the data should be sent. This option may be given multiple
times to send the data to more than one write plugin. If the plugin supports multiple instances,
the plugin's instance(s) must also be specified.

If no plugin is explicitly specified, the values will be sent to all available write plugins.

Single-instance plugin example:

<Target "write">
Plugin "rrdtool"
</Target>

Multi-instance plugin example:

<Plugin "write_graphite">
<Node "foo">
...
</Node>
<Node "bar">
...
</Node>
</Plugin>
...
<Target "write">
Plugin "write_graphite/foo"
</Target>

jump
Starts processing the rules of another chain, see "Flow control" above. If the end of that chain is
reached, or a stop condition is encountered, processing will continue right after the jump target,
i. e. with the next target or the next rule. This is similar to the -j command line option of
iptables, see iptables(8).

Available options:

Chain Name
Jumps to the chain Name. This argument is required and may appear only once.

Example:

<Target "jump">
Chain "foobar"
</Target>

Available matches
regex
Matches a value using regular expressions.

Available options:

Host Regex
Plugin Regex
PluginInstance Regex
Type Regex
TypeInstance Regex
Match values where the given regular expressions match the various fields of the identifier of a
value. If multiple regular expressions are given, all regexen must match for a value to match.

Invert false|true
When set to true, the result of the match is inverted, i.e. all value lists where all regular
expressions apply are not matched, all other value lists are matched. Defaults to false.

Example:

<Match "regex">
Host "customer[0-9]+"
Plugin "^foobar$"
</Match>

timediff
Matches values that have a time which differs from the time on the server.

This match is mainly intended for servers that receive values over the "network" plugin and write
them to disk using the "rrdtool" plugin. RRDtool is very sensitive to the timestamp used when
updating the RRD files. In particular, the time must be ever increasing. If a misbehaving client
sends one packet with a timestamp far in the future, all further packets with a correct time will be
ignored because of that one packet. What's worse, such corrupted RRD files are hard to fix.

This match lets one match all values outside a specified time range (relative to the server's time),
so you can use the stop target (see below) to ignore the value, for example.

Available options:

Future Seconds
Matches all values that are ahead of the server's time by Seconds or more seconds. Set to zero
for no limit. Either Future or Past must be non-zero.

Past Seconds
Matches all values that are behind of the server's time by Seconds or more seconds. Set to zero
for no limit. Either Future or Past must be non-zero.

Example:

<Match "timediff">
Future 300
Past 3600
</Match>

This example matches all values that are five minutes or more ahead of the server or one hour (or
more) lagging behind.

value
Matches the actual value of data sources against given minimum / maximum values. If a data-set
consists of more than one data-source, all data-sources must match the specified ranges for a
positive match.

Available options:

Min Value
Sets the smallest value which still results in a match. If unset, behaves like negative infinity.

Max Value
Sets the largest value which still results in a match. If unset, behaves like positive infinity.

Invert true|false
Inverts the selection. If the Min and Max settings result in a match, no-match is returned and
vice versa. Please note that the Invert setting only effects how Min and Max are applied to a
specific value. Especially the DataSource and Satisfy settings (see below) are not inverted.

DataSource DSName [DSName ...]
Select one or more of the data sources. If no data source is configured, all data sources will be
checked. If the type handled by the match does not have a data source of the specified name(s),
this will always result in no match (independent of the Invert setting).

Satisfy Any|All
Specifies how checking with several data sources is performed. If set to Any, the match succeeds
if one of the data sources is in the configured range. If set to All the match only succeeds if
all data sources are within the configured range. Default is All.

Usually All is used for positive matches, Any is used for negative matches. This means that with
All you usually check that all values are in a "good" range, while with Any you check if any
value is within a "bad" range (or outside the "good" range).

Either Min or Max, but not both, may be unset.

Example:

# Match all values smaller than or equal to 100. Matches only if all data
# sources are below 100.
<Match "value">
Max 100
Satisfy "All"
</Match>

# Match if the value of any data source is outside the range of 0 - 100.
<Match "value">
Min 0
Max 100
Invert true
Satisfy "Any"
</Match>

empty_counter
Matches all values with one or more data sources of type COUNTER and where all counter values are
zero. These counters usually never increased since they started existing (and are therefore
uninteresting), or got reset recently or overflowed and you had really, really bad luck.

Please keep in mind that ignoring such counters can result in confusing behavior: Counters which
hardly ever increase will be zero for long periods of time. If the counter is reset for some reason
(machine or service restarted, usually), the graph will be empty (NAN) for a long time. People may
not understand why.

hashed
Calculates a hash value of the host name and matches values according to that hash value. This makes
it possible to divide all hosts into groups and match only values that are in a specific group. The
intended use is in load balancing, where you want to handle only part of all data and leave the rest
for other servers.

The hashing function used tries to distribute the hosts evenly. First, it calculates a 32 bit hash
value using the characters of the hostname:

hash_value = 0;
for (i = 0; host[i] != 0; i++)
hash_value = (hash_value * 251) + host[i];

The constant 251 is a prime number which is supposed to make this hash value more random. The code
then checks the group for this host according to the Total and Match arguments:

if ((hash_value % Total) == Match)
matches;
else
does not match;

Please note that when you set Total to two (i. e. you have only two groups), then the least
significant bit of the hash value will be the XOR of all least significant bits in the host name. One
consequence is that when you have two hosts, "server0.example.com" and "server1.example.com", where
the host name differs in one digit only and the digits differ by one, those hosts will never end up
in the same group.

Available options:

Match Match Total
Divide the data into Total groups and match all hosts in group Match as described above. The
groups are numbered from zero, i. e. Match must be smaller than Total. Total must be at least
one, although only values greater than one really do make any sense.

You can repeat this option to match multiple groups, for example:

Match 3 7
Match 5 7

The above config will divide the data into seven groups and match groups three and five. One use
would be to keep every value on two hosts so that if one fails the missing data can later be
reconstructed from the second host.

Example:

# Operate on the pre-cache chain, so that ignored values are not even in the
# global cache.
<Chain "PreCache">
<Rule>
<Match "hashed">
# Divide all received hosts in seven groups and accept all hosts in
# group three.
Match 3 7
</Match>
# If matched: Return and continue.
Target "return"
</Rule>
# If not matched: Return and stop.
Target "stop"
</Chain>

Available targets
notification
Creates and dispatches a notification.

Available options:

Message String
This required option sets the message of the notification. The following placeholders will be
replaced by an appropriate value:

%{host}
%{plugin}
%{plugin_instance}
%{type}
%{type_instance}
These placeholders are replaced by the identifier field of the same name.

%{ds:name}
These placeholders are replaced by a (hopefully) human readable representation of the current
rate of this data source. If you changed the instance name (using the set or replace targets,
see below), it may not be possible to convert counter values to rates.

Please note that these placeholders are case sensitive!

Severity "FAILURE"|"WARNING"|"OKAY"
Sets the severity of the message. If omitted, the severity "WARNING" is used.

Example:

<Target "notification">
Message "Oops, the %{type_instance} temperature is currently %{ds:value}!"
Severity "WARNING"
</Target>

replace
Replaces parts of the identifier using regular expressions.

Available options:

Host Regex Replacement
Plugin Regex Replacement
PluginInstance Regex Replacement
TypeInstance Regex Replacement
Match the appropriate field with the given regular expression Regex. If the regular expression
matches, that part that matches is replaced with Replacement. If multiple places of the input
buffer match a given regular expression, only the first occurrence will be replaced.

You can specify each option multiple times to use multiple regular expressions one after another.

Example:

<Target "replace">
# Replace "example.net" with "example.com"
Host "\\<example.net\\>" "example.com"

# Strip "www." from hostnames
Host "\\<www\\." ""
</Target>

set Sets part of the identifier of a value to a given string.

Available options:

Host String
Plugin String
PluginInstance String
TypeInstance String
Set the appropriate field to the given string. The strings for plugin instance and type instance
may be empty, the strings for host and plugin may not be empty. It's currently not possible to
set the type of a value this way.

Example:

<Target "set">
PluginInstance "coretemp"
TypeInstance "core3"
</Target>

Backwards compatibility
If you use collectd with an old configuration, i. e. one without a Chain block, it will behave as it used
to. This is equivalent to the following configuration:

<Chain "PostCache">
Target "write"
</Chain>

If you specify a PostCacheChain, the write target will not be added anywhere and you will have to make
sure that it is called where appropriate. We suggest to add the above snippet as default target to your
"PostCache" chain.

Examples
Ignore all values, where the hostname does not contain a dot, i. e. can't be an FQDN.

<Chain "PreCache">
<Rule "no_fqdn">
<Match "regex">
Host "^[^\.]*$"
</Match>
Target "stop"
</Rule>
Target "write"
</Chain>

AUTHOR

       Florian Forster <octo@collectd.org>

5.5.1                                              2016-01-22                                   COLLECTD.CONF(5)

NAME

SYNOPSIS

DESCRIPTION

GLOBAL OPTIONS

PLUGIN OPTIONS

THRESHOLD CONFIGURATION

FILTER CONFIGURATION

SEE ALSO

AUTHOR