Ubuntu Manpage: PCPIntro - introduction to the Performance Co-Pilot (PCP)

NAME

       PCPIntro - introduction to the Performance Co-Pilot (PCP)

INTRODUCTION

       The  Performance  Co-Pilot (PCP) is a toolkit designed for monitoring and managing system-
       level performance.  These services are distributed and scalable to  accommodate  the  most
       complex system configurations and performance problems.

       PCP  supports  many  different  platforms,  including  (but not limited to) Linux, MacOSX,
       Solaris and Windows.  From a high-level PCP can be considered to contain  two  classes  of
       software utility:

       PCP Collectors
               These  are the parts of PCP that collect and extract performance data from various
               sources, e.g. the operating system kernel.

       PCP Monitors
               These are the parts of PCP that display data collected from  hosts  (or  archives)
               that  have  the PCP Collector installed.  Many monitor tools are available as part
               of the core PCP release, while other (typically graphical)  monitoring  tools  are
               available separately in the PCP GUI package.

       This  manual  entry  describes  the  high-level  features  and  options common to most PCP
       utilities available on all platforms.

OVERVIEW

The PCP architecture is distributed in the sense that any PCP tool may be executing
remotely. On the host (or hosts) being monitored, each domain of performance metrics,
whether the kernel, a service layer, a database management system, a web server, an
application, etc. requires a Performance Metrics Domain Agent (PMDA) which is
responsible for collecting performance measurements from that domain. All PMDAs are
controlled by the Performance Metrics Collector Daemon (pmcd(1)) on the same host.

Client applications (the monitoring tools) connect to pmcd(1), which acts as a router for
requests, by forwarding requests to the appropriate PMDA and returning the responses to
the clients. Clients may also access performance data from a PCP archive (created using
pmlogger(1)) for retrospective analysis.

Security philosophy
PCP redistributes a wealth of performance information within a host and across its
networks. The following security philosophy underlies the setting of several defaults
that control how much information is sent and received.

By default, the information exposed by PMCD about a host is approximately of the same
level of confidentiality as available to a completely unprivileged user on that host. So,
performance data that is available to be read completely freely on a machine may be made
available by PMCD to the network.

However, the host running PMCD and its network is not assumed to run only friendly
applications. Therefore, write type operations, including from the local host, are not
permitted by default.

These defaults may be overridden (expanded or reduced) in several ways, including by
specifying network ACLs in pmcd.conf, activating non-default PMDAs, or by using PMCD
connections that pass user credentials. For example, some PMDAs automatically provide
greater information for particular credentialed users or groups.

Applications
The following performance monitoring applications are primarily console based, typically
run directly from the command line, and are just a small subset of the tools available as
part of the base PCP package.

Each tool or command is documented completely in its own reference page.

pmstat Outputs an ASCII high-level summary of system performance.

pmie An inference engine that can evaluate predicate-action rules to perform alarms and
automate system management tasks.

pminfo Interrogate specific performance metrics and the metadata that describes them.

pmlogger
Generates PCP archives of performance metrics suitable for replay by most PCP
tools.

pmval Simple periodic reporting for some or all instances of a performance metric, with
optional VCR time control.

If the PCP GUI package is installed then the following additional tools are available.

pmchart
Displays trends over time of arbitrarily selected performance metrics from one or
more hosts.

pmtime Time control utility for coordinating the time between multiple tools (including
pmchart and pmval).

pmdumptext
Produce ASCII reports for arbitrary combinations of performance metrics.

COMMON COMMAND LINE ARGUMENTS

There is a set of common command line arguments that are used consistently by most PCP
tools.

-a archive
Performance metric information is retrospectively retrieved from the Performance
Co-Pilot (PCP) archive, previously generated by pmlogger(1).See pcp-
archive(5)forformatdocumentation. The -a and -h options are mutually exclusive.

archive is either the base name common to all of the physical files created by an
instance of pmlogger(1), or any one of the physical files, e.g. myarchive (base
name) or myarchive.meta (the metadata file) or myarchive.index (the temporal index)
or myarchive.0 (the first data volume of archive) or myarchive.0.bz2 or
myarchive.0.bz (the first data volume compressed with bzip2(1)) or myarchive.0.gz
or myarchive.0.Z or myarchive.0.z (the first data volume compressed with gzip(1)),
myarchive.1 or myarchive.3.bz2 or myarchive.42.gz etc.

-a archive[,archive,...]
An alternate form of -a for applications that are able to handle multiple archives.

-h hostname
Unless directed to another host by the -h option, or to an archive by the -a
option, the source of performance metrics will be the Performance Metrics Collector
Daemon (PMCD) on the local host. Refer to the PMCD HOST SPECIFICATION section
later for further details on the many options available when forming the hostname
specification, as well as a detailed description of the default local host
connection. The -a and -h options are mutually exclusive.

-s samples
The argument samples defines the number of samples to be retrieved and reported.
If samples is 0 or -s is not specified, the application will sample and report
continuously (in real time mode) or until the end of the PCP archive (in archive
mode).

-z Change the reporting timezone to the local timezone at the host that is the source
of the performance metrics, as identified via either the -h or -a options.

-Z timezone
By default, applications report the time of day according to the local timezone on
the system where the application is executed. The -Z option changes the timezone
to timezone in the format of the environment variable TZ as described in
environ(7).

INTERVAL SPECIFICATION AND ALIGNMENT

Most PCP tools operate with periodic sampling or reporting, and the -t and -A options may
be used to control the duration of the sample interval and the alignment of the sample
times.

-t interval
Set the update or reporting interval.

The interval argument is specified as a sequence of one or more elements of the
form
number[units]
where number is an integer or floating point constant (parsed using strtod(3)) and
the optional units is one of: seconds, second, secs, sec, s, minutes, minute, mins,
min, m, hours, hour, h, days, day and d. If the unit is empty, second is assumed.

In addition, the upper case (or mixed case) version of any of the above is also
acceptable.

Spaces anywhere in the interval are ignored, so 4 days 6 hours 30 minutes,
4day6hour30min, 4d6h30m and 4d6.5h are all equivalent.

Multiple specifications are additive, e.g. ``1hour 15mins 30secs'' is interpreted
as 3600+900+30 seconds.

-A align
By default samples are not necessarily aligned on any natural unit of time. The -A
option may be used to force the initial sample to be aligned on the boundary of a
natural time unit. For example -A 1sec, -A 30min and -A 1hour specify alignment on
whole seconds, half and whole hours respectively.

The align argument follows the syntax for an interval argument described above for
the -t option.

Note that alignment occurs by advancing the time as required, and that -A acts as a
modifier to advance both the start of the time window (see the next section) and
the origin time (if the -O option is specified).

TIME WINDOW SPECIFICATION

       Many PCP tools are designed to operate in some time window of interest, e.g. to  define  a
       termination  time  for real-time monitoring or to define a start and end time within a PCP
       archive log.

       In the absence of the -O and -A options to specify an initial sample time origin and  time
       alignment  (see above), the PCP application will retrieve the first sample at the start of
       the time window.

       The following options may be used to specify a time window of interest.

       -S starttime
              By default the time window commences immediately in real-time  mode,  or  coincides
              with  time  at the start of the PCP archive log in archive mode.  The -S option may
              be used to specify a later time for the start of the time window.

              The starttime parameter may be given in one of three forms (interval is the same as
              for the -t option as described above, datetime is described below):

              interval
                     To  specify  an  offset  from  the  current  time (in real-time mode) or the
                     beginning of a PCP archive (in archive mode) simply specify the interval  of
                     time  as  the argument.  For example -S 30min will set the start of the time
                     window to be exactly 30 minutes from now in real-time mode,  or  exactly  30
                     minutes from the start of a PCP archive.

              -interval
                     To  specify an offset from the end of a PCP archive log, prefix the interval
                     argument with a minus sign.  In this case, the  start  of  the  time  window
                     precedes  the time at the end of archive by the given interval.  For example
                     -S -1hour will set the start of the time  window  to  be  exactly  one  hour
                     before the time of the last sample in a PCP archive log.

              @datetime
                     To specify the calendar date and time (local time in the reporting timezone)
                     for the start of the time window, use the datetime syntax preceded by an  at
                     sign.  Refer to the datetime description below for detailed information.

       -T endtime
              By  default  the end of the time window is unbounded (in real-time mode) or aligned
              with the time at the end of a PCP archive log (in archive mode).  The -T option may
              be used to specify an earlier time for the end of the time window.

              The  endtime  parameter may be given in one of three forms (interval is the same as
              for the -t option as described above, datetime is described below):

              interval
                     To specify an offset from the start  of  the  time  window  simply  use  the
                     interval  of time as the argument.  For example -T 2h30m will set the end of
                     the time window to be 2 hours and 30 minutes after the  start  of  the  time
                     window.

              -interval
                     To  specify  an  offset  back from the time at the end of a PCP archive log,
                     prefix the interval argument with a minus sign.  For example  -T  -90m  will
                     set  the end of the time window to be 90 minutes before the time of the last
                     sample in a PCP archive log.

              @datetime
                     To specify the calendar date and time (local time in the reporting timezone)
                     for  the  end  of the time window, use the datetime syntax preceded by an at
                     sign.  Refer to the datetime description below for detailed information.

       -O origin
              By default samples are fetched from the start of the time window  (see  description
              of -S option) to the end of the time window (see description of -T option).  The -O
              option allows the specification of an origin within the time window to be  used  as
              the initial sample time.  This is useful for interactive use of a PCP tool with the
              pmtime(1) VCR replay facility.

              The origin argument accepted by -O conforms to the same syntax and semantics as the
              starttime argument for the -T option.

              For  example  -O -0 specifies that the initial position should be at the end of the
              time window; this is most useful when wishing to replay  ``backwards''  within  the
              time window.

       The datetime argument for the -O, -S and -T options consists of:
                 date time zone day relative
       A  date can be one of: YY-MM-DD, MM/DD/YY, DD Month YYYY, or Month DD YYYY.  A time can be
       one of: HH:MM:SS, HH:MM.  HH:MM can use either the 12 hour (via an am or pm suffix) or  24
       hour  convention.   A  day  of  the  week can be a spelled out day of the week, optionally
       preceded by an ordinal number such as second tuesday.  A zone is  a  time  zone  value  as
       specified  by  the  tzselect(1)  command.   A  relative  time  can be a time unit that is:
       preceded by a cardinal number such as 1 year or 2 months, preceded  by  one  of  the  time
       words this or last, or succeeded by the time word ago.  A relative time can also be one of
       the time words: yesterday, today,  tomorrow,  now.   Examples  of  datetime  strings  are:
       1996-03-04 13:07:47 EST Mon, 1996-03-05 14:07:47 EST -1hour, Mon Mar  4 13:07:47 1996, Mar
       4 1996, Mar 4, Mar, 13:07:50 or 13:08.

       For any missing low order fields, the default value of 0 is assumed for hours, minutes and
       seconds,  1 for day of the month and Jan for months.  Hence, the following are equivalent:
       -S '@ Mar 1996' and -S '@ Mar 1 00:00:00 1996'.

       If any high order fields are missing, they are filled in by starting with the year,  month
       and  day  from  the  current time (real-time mode) or the time at the beginning of the PCP
       archive log (archive mode) and advancing the time until it matches  the  fields  that  are
       specified.   So,  for example if the time window starts by default at ``Mon Mar 4 13:07:47
       1996'', then -S @13:10 corresponds to 13:10:00  on  Mon  Mar  4,  1996,  while  -S  @10:00
       corresponds to 10:00:00 on Tue Mar 5, 1996 (note this is the following day).

       For  greater  precision  than  afforded  by  datetime(3),  the  seconds component may be a
       floating point number.

PERFORMANCE METRICS - NAMES AND IDENTIFIERS

The number of performance metric names supported by PCP on most platforms ranges from many
hundreds to several thousand. The PCP libraries and applications use an internal
identification scheme that unambiguously associates a single integer with each known
performance metric. This integer is known as the Performance Metric Identifier, or PMID.
Although not a requirement, PMIDs tend to have global consistency across all systems, so a
particular performance metric usually has the same PMID.

For all users and most applications, direct use of the PMIDs would be inappropriate (e.g.
this would limit the range of accessible metrics, make the code hard to maintain, force
the user interface to be particularly baroque, etc.). Hence a Performance Metrics Name
Space (PMNS) is used to provide external names and a hierarchic classification for
performance metrics. A PMNS is represented as a tree, with each node having a label, a
pointer to either a PMID (for leaf nodes) or a set of descendent nodes in the PMNS (for
non-leaf nodes).

A node label must begin with an alphabetic character, followed by zero or more characters
drawn from the alphabetics, the digits and character `_´ (underscore). For alphabetic
characters in a node label, upper and lower case are distinguished.

By convention, the name of a performance metric is constructed by concatenation of the
node labels on a path through the PMNS from the root node to a leaf node, with a ``.'' as
a separator. The root node in the PMNS is unlabeled, so all names begin with the label
associated with one of the descendent nodes below the root node of the PMNS, e.g.
kernel.percpu.syscall. Typically (although this is not a requirement) there would be at
most one name for each PMID in a PMNS. For example kernel.all.cpu.idle and disk.dev.read
are the unique names for two distinct performance metrics, each with a unique PMID.

Groups of related PMIDs may be named by naming a non-leaf node in the PMNS tree, e.g.
disk.

The default local PMNS used by pmcd is located at $PCP_VAR_DIR/pmns/root however the
environment variable PMNS_DEFAULT may be set to the full pathname of a different PMNS
which will then be used as the default local PMNS.

Most applications do not use the local PMNS directly, but rather import parts of the PMNS
as required from the same place that performance metrics are fetched, i.e. from pmcd(1)
for live monitoring or from a PCP archive for retrospective monitoring.

To explore the PMNS use pminfo(1), or if the PCP GUI package is installed the New Chart
and Metric Search windows within pmchart(1).

PERFORMANCE METRIC SPECIFICATIONS

       In   configuration   files   and  (to  a  lesser  extent)  command  line  options,  metric
       specifications adhere to the following syntax rules.

       If the source of performance metrics is real-time from pmcd(1) then the accepted syntax is
                 host:metric[instance1,instance2,...]

       If the source of performance metrics is a PCP archive log then the accepted syntax is
                 archive/metric[instance1,instance2,...]

       The host:, archive/ and [instance1,instance2,...]  components are all optional.

       The , delimiter in the list of instance names may be replaced by white space.

       Special characters in instance names may be escaped by  surrounding  the  name  in  double
       quotes or preceding the character with a backslash.

       White space is ignored everywhere except within a quoted instance name.

       An  empty  instance  is  silently  ignored,  and  in  particular  ``[]'' is the same as no
       instance, while ``[one,,,two]'' is parsed as specifying just the two instances ``one'' and
       ``two''.

       As  a  special  case,  if  the  host  is  the single character ``@'' then this refers to a
       PM_CONTEXT_LOCAL source, see pmNewContext(3).

SECURE PMCD CONNECTIONS

       Since PCP version 3.6.11, a monitor can  explicitly  request  a  secure  connection  to  a
       collector host running pmcd(1) or pmproxy(1) using the PM_CTXFLAG_SECURE context flag.  If
       the PCP Collector host supports this feature - refer to the pmcd.feature.secure metric for
       confirmation  of  this  -  a  TLS/SSL  (Transport  Layer Security or Secure Sockets Layer)
       connection can be established which uses public key cryptography and  related  techniques.
       These  features  aim  to  prevent  eavesdropping and data tampering from a malicious third
       party, as well as providing server-side  authentication  (confident  identification  of  a
       server by a client) which can be used to guard against man-in-the-middle attacks.

       A  secure  pmcd connection requires use of certificate-based authentication.  The security
       features offered by pmcd and pmproxy are implemented using the Network  Security  Services
       (NSS)  APIs  and  utilities.   The  NSS  certutil  tool can be used to create certificates
       suitable for establishing trust between PCP monitor and collector hosts.

       A complete description is beyond the scope of this document, refer to the PCP ENVIRONMENT,
       FILES and SEE ALSO sections for detailed information.  This includes links to tutorials on
       the steps involved in setting up the available security features.

PMCD HOST SPECIFICATION

In the absence of an explicit host name specification, most tools will default to the
local host in live update mode. In PCP releases since 3.8.4 onward, this results in an
efficient local protocol being selected - typically a Unix domain socket. If this option
is used (which can also be explicitly requested via the unix: host specification described
below), it is important to note that all connections will be automatically authenticated.
In other words, the credentials of the user invoking a client tool will automatically be
made available to pmcd(1) and all of its PMDAs, on the users behalf, such that results can
be customized to the privilege levels of individual users.

Names of remote hosts running the pmcd(1) daemon can of course also be provided to request
a remote host be used. The most basic form of pmcd host specification is a simple host
name, possibly including the domain name if necessary. However, this can be extended in a
number of ways to further refine attributes of the connection made to pmcd.

The pmcd port number and also optional pmproxy(1) hostname and its port number, can be
given as part of the host specification, since PCP version 3.0. These supersede (and
override) the old-style PMCD_PORT, PMPROXY_HOST and PMPROXY_PORT environment variables.

The following are valid hostname specifications that specify connections to pmcd on host
nas1.servers.com with/without a list of ports, with/without a pmproxy(1) connection
through a firewall, and with IPv6 and IPv4 addresses as shown.

$ pcp -h nas1.servers.com:44321,4321@firewall.servers.com:44322
$ pcp -h nas1.servers.com:44321@firewall.servers.com:44322
$ pcp -h nas1.servers.com:44321@firewall.servers.com
$ pcp -h nas1.servers.com@firewall.servers.com
$ pcp -h nas1.servers.com:44321
$ pcp -h [fe80::2ad2:44ff:fe88:e4f1%p2p1]
$ pcp -h 192.168.0.103

In addition, ``connection attributes'' can also be specified. These include username,
password (can be given interactively and may depend on the authentication mechanism
employed), whether to target a specific running container, whether to use secure
(encrypted) or native (naked) protocol, and so on. The previous examples all default to
native protocol, and use no authentication. This can be altered, as in the following
examples.

$ pcp -h pcps://app2.servers.com?container=cae8e6edc0d5
$ pcp -h pcps://nas1.servers.com:44321?username=tanya&method=gssapi
$ pcp -h pcps://nas2.servers.com@firewalls.r.us?method=plain
$ pcp -h pcp://nas3.servers.com
$ pcp -h 192.168.0.103?container=cae8e6edc0d5,method=digest-md5
$ pcp -h unix:
$ pcp -h local:

The choice of authentication method, and other resulting parameters like username,
optionally password, etc, depends on the SASL2 configuration used by each (remote) pmcd.
Tutorials are available specifying various aspects of configuring the authentication
module(s) used, these fine details are outside the scope of this document.

In all situations, host names can be used interchangeably with IPv4 or IPv6 addressing
(directly), as shown above. In the case of an IPv6 address, the full address must be
enclosed by square brackets and the scope (interface) must also be specified.

The final local: example above is now the default for most tools. This connection is an
automatically authenticated local host connection on all platforms that support Unix
domain sockets. No password is required and authentication is automatic. This is also
the most efficient (lowest overhead) communication channel available.

The difference between unix: and local: is that the former is a strict Unix domain socket
specification (connection fails if it cannot connect that way), whereas the latter has a
more forgiving fallback to using localhost (i.e. a regular Inet socket connection is used
when Unix domain socket connections are unavailable).

ENVIRONMENT

In addition to the PCP run-time environment and configuration variables described in the
PCP ENVIRONMENT section below, the following environment variables apply to all
installations.

PCP_CONSOLE
When set, this changes the default console from /dev/tty (on Unix) or CON: (on
Windows) to be the specified console. The special value of none can be used to
indicate no console is available for use. This is used in places where console-
based tools need to interact with the user, and in particular is used when
authentication is being performed.

PCP_DEBUG
When set, this variable provides an alternate way to initialize the value used to
control diagnostic and debug output (the default value is 0 to suppress this
output). The value for $PCP_DEBUG should be a decimal integer, see pmdbg(1) for a
description of the supported values.

PCP_DERIVED_CONFIG
When set, this variable defines a colon separated list of files and/or directories
(the syntax is the same as for the $PATH variable for sh(1)). The components are
expanded into a list of files as follows: if a component of $PCP_DERIVED_CONFIG is
a file, then that file is added to the list, else if a component is a directory
then recursive descent is used to enumerate all files below that directory and
these are added to the list.

Each file in the resulting list is assumed to contain definitions of derived
metrics as per the syntax described in pmLoadDerivedConfig(3), and these are loaded
in order.

Derived metrics may be used to extend the available metrics with new (derived)
metrics using simple arithmetic expressions.

If PCP_DERIVED_CONFIG is set, the derived metric definitions are processed
automatically as each new source of performance metrics is established (i.e. each
time a pmNewContext(3) is called) or when requests are made against the PMNS.

Any component in the $PCP_DERIVED_CONFIG list or the expanded list of files that is
not a file, or is not a directory or is not accessible (due to permissions or a bad
symbolic link) will be silently ignored.

PCP_SECURE_SOCKETS
When set, this variable forces any monitor tool connections to be established using
the certificate-based secure sockets feature. If the connections cannot be
established securely, they will fail.

PCP_SECURE_DB_METHOD
With secure socket connections, the certificate and key database is stored using
the sql: method by default. Use PCP_SECURE_DB_METHOD to override the default, most
usually setting the value to the empty string (for the older database methods).

PCP_STDERR
Many PCP tools support the environment variable PCP_STDERR, which can be used to
control where error messages are sent. When unset, the default behavior is that
``usage'' messages and option parsing errors are reported on standard error, other
messages after initial startup are sent to the default destination for the tool,
i.e. standard error for ASCII tools, or a dialog for GUI tools.

If PCP_STDERR is set to the literal value DISPLAY then all messages will be
displayed in a dialog. This is used for any tools launched from the a Desktop
environment.

If PCP_STDERR is set to any other value, the value is assumed to be a filename, and
all messages will be written there.

PMCD_CONNECT_TIMEOUT
When attempting to connect to a remote pmcd(1) on a machine that is booting, the
connection attempt could potentially block for a long time until the remote machine
finishes its initialization. Most PCP applications and some of the PCP library
routines will abort and return an error if the connection has not been established
after some specified interval has elapsed. The default interval is 5 seconds.
This may be modified by setting PMCD_CONNECT_TIMEOUT in the environment to a real
number of seconds for the desired timeout. This is most useful in cases where the
remote host is at the end of a slow network, requiring longer latencies to
establish the connection correctly.

PMCD_RECONNECT_TIMEOUT
When a monitor or client application loses a connection to a pmcd(1), the
connection may be re-established by calling a service routine in the PCP library.
However, attempts to reconnect are controlled by a back-off strategy to avoid
flooding the network with reconnection requests. By default, the back-off delays
are 5, 10, 20, 40 and 80 seconds for consecutive reconnection requests from a
client (the last delay will be repeated for any further attempts after the fifth).
Setting the environment variable PMCD_RECONNECT_TIMEOUT to a comma separated list
of positive integers will re-define the back-off delays, e.g. setting
PMCD_RECONNECT_TIMEOUT to ``1,2'' will back-off for 1 second, then attempt another
connection request every 2 seconds thereafter.

PMCD_REQUEST_TIMEOUT
For monitor or client applications connected to pmcd(1), there is a possibility of
the application "hanging" on a request for performance metrics or metadata or help
text. These delays may become severe if the system running pmcd crashes, or the
network connection is lost. By setting the environment variable
PMCD_REQUEST_TIMEOUT to a number of seconds, requests to pmcd will timeout after
this number of seconds. The default behavior is to be willing to wait 10 seconds
for a response from every pmcd for all applications.

PMCD_WAIT_TIMEOUT
When pmcd(1) is started from $PCP_RC_DIR/pcp then the primary instance of
pmlogger(1) will be started if the configuration flag pmlogger is chkconfig(8)
enabled and pmcd is running and accepting connections.

The check on pmcd's readiness will wait up to PMCD_WAIT_TIMEOUT seconds. If pmcd
has a long startup time (such as on a very large system), then PMCD_WAIT_TIMEOUT
can be set to provide a maximum wait longer than the default 60 seconds.

PMNS_DEFAULT
If set, then interpreted as the full pathname to be used as the default local PMNS
for pmLoadNameSpace(3). Otherwise, the default local PMNS is located at
$PCP_VAR_DIR/pcp/pmns/root for base PCP installations.

PCP_COUNTER_WRAP
Many of the performance metrics exported from PCP agents have the semantics of
counter meaning they are expected to be monotonically increasing. Under some
circumstances, one value of these metrics may smaller than the previously fetched
value. This can happen when a counter of finite precision overflows, or when the
PCP agent has been reset or restarted, or when the PCP agent is exporting values
from some underlying instrumentation that is subject to some asynchronous
discontinuity.

The environment variable PCP_COUNTER_WRAP may be set to indicate that all such
cases of a decreasing ``counter'' should be treated as a counter overflow, and
hence the values are assumed to have wrapped once in the interval between
consecutive samples. This ``wrapping'' behavior was the default in earlier PCP
versions, but by default has been disabled in PCP release from version 1.3 on.

PMDA_PATH
The PMDA_PATH environment variable may be used to modify the search path used by
pmcd(1) and pmNewContext(3) (for PM_CONTEXT_LOCAL contexts) when searching for a
daemon or DSO PMDA. The syntax follows that for PATH in sh(1), i.e. a colon
separated list of directories, and the default search path is
``/var/pcp/lib:/usr/pcp/lib'', (or ``/var/lib/pcp/lib'' on Linux, depending on the
value of the $PCP_VAR_DIR environment variable).

PMCD_PORT
The TPC/IP port(s) used by pmcd(1) to create the socket for incoming connections
and requests, was historically 4321 and more recently the officially registered
port 44321; in the current release, both port numbers are used by default as a
transitional arrangement. This may be over-ridden by setting PMCD_PORT to a
different port number, or a comma-separated list of port numbers. If a non-default
port is used when pmcd is started, then every monitoring application connecting to
that pmcd must also have PMCD_PORT set in their environment before attempting a
connection.

The following environment variables are relevant to installations in which pmlogger(1),
the PCP archive logger, is used.

PMLOGGER_PORT
The environment variable PMLOGGER_PORT may be used to change the base TCP/IP port
number used by pmlogger(1) to create the socket to which pmlc(1) instances will try
and connect. The default base port number is 4330. When used, PMLOGGER_PORT
should be set in the environment before pmlogger is executed.

PMLOGGER_REQUEST_TIMEOUT
When pmlc(1) connects to pmlogger(1), there is a remote possibility of pmlc
"hanging" on a request for information as a consequence of a failure of the network
or pmlogger. By setting the environment variable PMLOGGER_REQUEST_TIMEOUT to a
number of seconds, requests to pmlogger will timeout after this number of seconds.
The default behavior is to be willing to wait forever for a response from each
request to a pmlogger. When used, PMLOGGER_REQUEST_TIMEOUT should be set in the
environment before pmlc is executed.

If you have the PCP product installed, then the following environment variables are
relevant to the Performance Metrics Domain Agents (PMDAs).

PMDA_LOCAL_PROC
Use this variable has been deprecated and it is now ignored. If the ``proc'' PMDA
is configured as a DSO for use with pmcd(1) on the local host then all of the
``proc'' metrics will be available to applications using a PM_CONTEXT_LOCAL
context.

The previous behaviour was that if this variable was set, then a context
established with the type of PM_CONTEXT_LOCAL will have access to the ``proc'' PMDA
to retrieve performance metrics about individual processes.

PMDA_LOCAL_SAMPLE
Use this variable has been deprecated and it is now ignored. If the ``sample''
PMDA is configured as a DSO for use with pmcd(1) on the local host then all of the
``sample'' metrics will be available to applications using a PM_CONTEXT_LOCAL
context.

The previous behaviour was that if this variable was set, then a context
established with the type of PM_CONTEXT_LOCAL will have access to the ``sample''
PMDA if this optional PMDA has been installed locally.

PMIECONF_PATH
If set, pmieconf(1) will form its pmieconf(5) specification (set of parameterized
pmie(1) rules) using all valid pmieconf files found below each subdirectory in this
colon-separated list of subdirectories. If not set, the default is
$PCP_VAR_DIR/config/pmieconf.

FILES

/etc/pcp.conf
Configuration file for the PCP runtime environment, see pcp.conf(5).
/etc/pki/nssdb
Optionally contains a Network Security Services database with a "PCP Collector"
certificate providing trusted identification for the collector host.
$HOME/.pcp
User-specific directories containing configuration files for customisation of
the various monitor tools, such as pmchart(1).
$HOME/.pki/nssdb
A shared Network Security Services (NSS) database directory containing per-user
certificates identifying known valid remote pmcd collector hosts. The NSS
certutil tool is one of several that can be used to maintain this database.
$PCP_RC_DIR/pcp
Script for starting and stopping pmcd(1).
$PCP_PMCDCONF_PATH
Control file for pmcd(1).
$PCP_PMCDOPTIONS_PATH
Command line options passed to pmcd(1) when it is started from $PCP_RC_DIR/pcp.
All the command line option lines should start with a hyphen as the first
character. This file can also contain environment variable settings of the form
"VARIABLE=value".
$PCP_BINADM_DIR
Location of PCP utilities for collecting and maintaining PCP archives, PMDA help
text, PMNS files etc.
$PCP_PMDAS_DIR
Parent directory of the installation directory for Dynamic Shared Object (DSO)
PMDAs.
$PCP_RUN_DIR/pmcd.pid
If pmcd is running, this file contains an ascii decimal representation of its
process ID.
$PCP_LOG_DIR/pmcd
Default location of log files for pmcd(1), current directory for running PMDAs.
Archives generated by pmlogger(1) are generally below $PCP_LOG_DIR/pmlogger.
$PCP_LOG_DIR/pmcd/pmcd.log
Diagnostic and status log for the current running pmcd(1) process. The first
place to look when there are problems associated with pmcd.
$PCP_LOG_DIR/pmcd/pmcd.log.prev
Diagnostic and status log for the previous pmcd(1) instance.
$PCP_LOG_DIR/NOTICES
Log of pmcd(1) and PMDA starts, stops, additions and removals.
$PCP_VAR_DIR/config
Contains directories of configuration files for several PCP tools.
$PCP_SYSCONF_DIR/pmcd/rc.local
Local script for controlling PCP boot, shutdown and restart actions.
$PCP_VAR_DIR/pmns
Directory containing the set of PMNS files for all installed PMDAs.
$PCP_VAR_DIR/pmns/root
The ASCII pmns(5) exported by pmcd(1) by default. This PMNS is be the super set
of all other PMNS files installed in $PCP_VAR_DIR/pmns.
In addition, if the PCP product is installed the following files and directories are
relevant.
$PCP_LOG_DIR/NOTICES
In addition to the pmcd(1) and PMDA activity, may be used to log alarms and notices
from pmie(1) via pmpost(1).
$PCP_PMLOGGERCONTROL_PATH
Control file for pmlogger(1) instances launched from $PCP_RC_DIR/pcp and/or managed
by pmlogger_check(1) and pmlogger_daily(1) as part of a production PCP archive
collection setup.

PCP ENVIRONMENT

       Environment variables with the prefix PCP_ are used to parameterize the file and directory
       names used by PCP.  On each installation, the file /etc/pcp.conf contains the local values
       for these variables.  The $PCP_CONF  variable  may  be  used  to  specify  an  alternative
       configuration file, as described in pcp.conf(5).