Provided by: collectd-core_4.10.1-2.1ubuntu7_amd64 bug

NAME

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

SYNOPSIS

         BaseDir "/path/to/data/"
         PIDFile "/path/to/pidfile/collectd.pid"
         Server  "123.123.123.123" 12345

         LoadPlugin cpu
         LoadPlugin load
         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.

       The syntax of this config file is similar to the config file of the famous Apache
       Webserver. Each line contains either a key-value-pair or a section-start or -end. Empty
       lines and everything after the hash-symbol `#' is ignored. Values are either string,
       enclosed in double-quotes, (floating-point-)numbers or a boolean expression, i. e. either
       true or false. String containing of only alphanumeric characters and underscores do not
       need to be quoted. 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, the
       "LoadPlugin" option must occur before the "<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. There must be at least one such line or collectd will be
           mostly useless.

       Include Path
           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"

           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.

       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 "THRESHOLD CONFIGURATION" below.

       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 plugin that do network-IO. Setting this to a value higher than
           the number of plugins you've loaded is totally useless.

       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".

           Using this feature (i. e. setting this option to true) is recommended.  However, to
           preserve backwards compatibility the default is set to false.  The sample config file
           that is installed with "make install" includes a line which sets this option, though,
           so that default installations will have this setting enabled.

       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 configfile.

       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 "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 following options are accepted by the "apache"-plugin:

       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.

       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.

   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.

   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.

       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.

   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/"
          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.

       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.

       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 "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"
             <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.

       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.

       MeasureResponseTime true|false
           Measure response time 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 option is set to true, Match blocks are optional.

   Plugin "curl_json"
       The curl_json plugin uses libcurl (<http://curl.haxx.se/>) and libyajl
       (<http://www.lloydforge.org/projects/yajl/>) to retrieve JSON data via cURL. This can be
       used to collect values from CouchDB documents (which are stored JSON notation), for
       example.

       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>

       Another CouchDB example: The following example will collect the status values from each
       database:

         <URL "http://localhost:5984/_all_dbs">
           Instance "dbs"
           <Key "*/doc_count">
             Type "gauge"
           </Key>
           <Key "*/doc_del_count">
             Type "counter"
           </Key>
           <Key "*/disk_size">
             Type "bytes"
           </Key>
         </URL>

       In the Plugin block, there may be one or more URL blocks, each defining a URL to be
       fetched via HTTP (using libcurl) and one or more Key blocks.  The Key string argument must
       be in a path format, which is used to collect a value from a JSON map object. If a path
       element of Key is the * wildcard, the values for all keys will be collectd.

       The following options are valid within URL blocks:

       Instance Instance
           Sets the plugin instance to Instance.

       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.

       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.

       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"

            <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 via HTTP (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).

       User User =item Password Password =item VerifyPeer true|false =item VerifyHost true|false
       =item CACert CA Cert File
           These options behave exactly equivalent to the appropriate options of the cURL and
           cURL-JSON plugins. 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.

       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/
           <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/
           <http://libdbi-drivers.sourceforge.net/>. However, the options "host", "username",
           "password", and "dbname" seem to be de facto standards.

           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.

       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.

   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).

       ReportReserved true|false
           When enabled, the blocks reserved for root are reported separately. When disabled (the
           default for backwards compatibility reasons) the reserved space will be included in
           the "free" space.

           When disabled, the "df" type will be used to store "free" and "used" space. The mount
           point or disk name (see option ReportByDevice) is used as type instance in this case
           (again: backwards compatibility).

           When enabled, the type "df_complex" is used and three files are created. The mount
           point or disk name is used as plugin instance and the type instance is set to "free",
           "reserved" and "used" as appropriate.

           Enabling this option is recommended.

       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.

   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.

   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 "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 "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.

       TranslateDevicename true|false
           If enabled, translate the disk names to major/minor device numbers (e. g. "8-0" for
           /dev/sda). For backwards compatibility this defaults to true but it's recommended to
           disable it as it will probably be removed in the next major version.

   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.

   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]]
           Select the rules to count. 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 "libvirt"
       This plugin allows CPU, disk and network load to be collected for virtualized guests on
       the machine. This means that these characteristics can be collected for guest systems
       without installing any software on them - collectd only runs on the hosting 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 libvirt 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").

   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 "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 "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/>

       Host Hostname
           Hostname to connect to. Defaults to 127.0.0.1.

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

   Plugin "modbus"
       The modbus plugin connects to a Modbus "slave" via Modbus/TCP 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
          Type voltage
          Instance "input-1"
        </Data>

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

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

           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
               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
               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".

           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 TCP 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
       complaint 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
           </Database>

           <Database bar>
             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.

       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).  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.

       MasterStats true|false
       SlaveStats true|false
           Enable the collection of master / slave statistics in a replication setup.

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

   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>

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

       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

       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.

   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. For example:

        <Plugin "network">
          Server "collectd.internal.tld"
          <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.

       <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.

       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.

       CacheFlush Seconds
           For each host/plugin/type combination the "network plugin" caches the time of the last
           value being sent or received. Every Seconds seconds the plugin searches and removes
           all entries that are older than Seconds seconds, thus freeing the unused memory again.
           Since this process is somewhat expensive and normally doesn't do much, this value
           should not be too small. The default is 1800 seconds, but setting this to 86400
           seconds (one day) will not do much harm either.

       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.

       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.

   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.

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

   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.

       Currently only temperature sensors (sensors with the family code 10, 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.

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

       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
           Selects sensors to collect or to ignore, depending on IgnoreSelected, see below.
           Sensors are specified without the family byte at the beginning, to you'd use
           "F10FCA000800", and not include the leading 10. family byte and point.

       IgnoreSelected true|false
           If no configuration if 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.

       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 "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 OracleAX Call Interface (OCI) to connect to an OracleAX
       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".

       Username Username
           Username used for authentication.

       Password Password
           Password used for authentication.

       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.

   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.

       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>

           <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>
         </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.

       Query sql query statement
           This is a deprecated synonym for Statement. It will be removed in version 5 of
           collectd.

       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.

           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.

       Column type [type instance]
           This is a deprecated alternative to a Result block. It will be removed in version 5 of
           collectd. It is equivalent to the following Result block:

             <Result>
               Type I<type>
               InstancePrefix I<type instance>
               ValuesFrom I<name of the x. column>
             </Result>

           The order of the Column options defines which columns of the query result should be
           used. The first option specifies the data found in the first column, the second option
           that of the second column, and so on.

       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.

       MinPGVersion version
       MaxPGVersion version
           These are deprecated synonyms for MinVersion and MaxVersion respectively. They will be
           removed in version 5 of collectd.

       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.

       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.

       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.

       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
           Specify a query which should be executed for 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". Else, the specified queries are used 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 "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.

   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. Per default RRD-files are generated
           beneath the daemon's working directory, i. e. the BaseDir.

       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.

       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/>.

       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 "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 "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.

   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.
           ItaXXs 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"
             <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.

       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
               The matched number is a counter. Simply sets the internal counter to this value.

           CounterAdd
               Add the matched value to the internal counter.

           CounterInc
               Increase the internal counter by one. This DSType is the only one that does not
               use the matched subexpression, but simply counts 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 CounterSet and CounterAdd interpret the submatch as an integer
           using strtoll(3). CounterInc does 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 "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.

   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 "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 "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.

       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.

   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 "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/ <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_http"
       This output plugin submits values to an http server by POST them using the PUTVAL plain-
       text protocol. Each destination you want to post data to needs to have one URL block,
       within which the destination can be configured further, for example by specifying
       authentication data.

       Synopsis:

        <Plugin "write_http">
          <URL "http://example.com/post-collectd">
            User "collectd"
            Password "weCh3ik0"
          </URL>
        </Plugin>

       URL blocks need one string argument which is used as the URL to which data is posted. The
       following options are understood within URL blocks.

       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.

       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.

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.

        <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>
        </Threshold>

       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.

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:

            <Match "foobar">
            </Match>

       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:

            <Target "stop">
            </Target>

   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 no plugin is explicitly specified, the values will be sent to all available write
           plugins.

           Example:

            <Target "write">
              Plugin "rrdtool"
            </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 "FATAL"|"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>

SEE ALSO

       collectd(1), collectd-exec(5), collectd-perl(5), collectd-unixsock(5), types.db(5),
       hddtemp(8), iptables(8), kstat(3KSTAT), mbmon(1), psql(1), regex(7), rrdtool(1),
       sensors(1)

AUTHOR

       Florian Forster <octo@verplant.org>