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COLLECTD(1)                        collectd                        COLLECTD(1)
NAME
       collectd - System statistics collection daemon
SYNOPSIS
       collectd [options]
DESCRIPTION
       collectd is a daemon that receives system statistics and makes them
       available in a number of ways. The main daemon itself doesn't have any
       real functionality apart from loading, querying and submitting to
       plugins. For a description of available plugins please see "PLUGINS"
       below.
OPTIONS
       Most of collectd's configuration is done using using a configfile. See
       collectd.conf(5) for an in-depth description of all options.
       -C <config-file>
           Specify an alternative config file. This is the place to go when
           you wish to change collectd's behavior. The path may be relative to
           the current working directory.
       -t  Test the configuration only. The program immediately exits after
           parsing the config file. A return code not equal to zero indicates
           an error.
       -T  Test the plugin read callbacks only. The program immediately exits
           after invoking the read callbacks once. A return code not equal to
           zero indicates an error.
       -P <pid-file>
           Specify an alternative pid file. This overwrites any settings in
           the config file. This is thought for init-scripts that require the
           PID-file in a certain directory to work correctly. For everyday-
           usage use the PIDFile config-option.
       -B  If set, collectd will not try to create its base directory. If the
           base directory does not exist, it will exit rather than trying to
           create the directory.
       -f  Don't fork to the background. collectd will also not close standard
           file descriptors, detach from the session nor write a pid file.
           This is mainly thought for 'supervising' init replacements such as
           runit. If using upstart or systemd though, starting with version
           5.5.0 collectd is able to notify these two init replacements, and
           does require forking to the background for process supervision. The
           contrib/ directory has sample upstart and systemd configuration
           files.
       -h  Output usage information and exit.
PLUGINS
       As noted above, the real power of collectd lies within its plugins. A
       (hopefully complete) list of plugins and short descriptions can be
       found in the README file that is distributed with the sourcecode. If
       you're using a package it's a good bet to search somewhere near
       /usr/share/doc/collectd.
       There are two big groups of plugins, input and output plugins:
       o   Input plugins are queried periodically. They somehow acquire the
           current value of whatever they where designed to work with and
           submit these values back to the daemon, i. e. they "dispatch" the
           values. As an example, the "cpu plugin" reads the current cpu-
           counters of time spent in the various modes (user, system, nice,
           ...) and dispatches these counters to the daemon.
       o   Output plugins get the dispatched values from the daemon and does
           something with them. Common applications are writing to RRD-files,
           CSV-files or sending the data over a network link to a remote box.
       Of course not all plugins fit neatly into one of the two above
       categories. The "network plugin", for example, is able to send (i. e.
       "write") and receive (i. e. "dispatch") values. Also, it opens a socket
       upon initialization and dispatches the values when it receives them and
       isn't triggered at the same time the input plugins are being read. You
       can think of the network receive part as working asynchronous if it
       helps.
       In addition to the above, there are "logging plugins". Right now those
       are the "logfile plugin" and the "syslog plugin". With these plugins
       collectd can provide information about issues and significant
       situations to the user.  Several loglevels let you suppress
       uninteresting messages.
       Starting with version 4.3.0 collectd has support for monitoring. This
       is done by checking thresholds defined by the user. If a value is out
       of range, a notification will be dispatched to "notification plugins".
       See collectd.conf(5) for more detailed information about threshold
       checking.
       Please note that some plugins, that provide other means of
       communicating with the daemon, have manpages of their own to describe
       their functionality in more detail. In particular those are
       collectd-email(5), collectd-exec(5), collectd-perl(5),
       collectd-snmp(5), and collectd-unixsock(5)
SIGNALS
       collectd accepts the following signals:
       SIGINT, SIGTERM
           These signals cause collectd to shut down all plugins and
           terminate.
       SIGUSR1
           This signal causes collectd to signal all plugins to flush data
           from internal caches. E. g. the "rrdtool plugin" will write all
           pending data to the RRD files. This is the same as using the "FLUSH
           -1" command of the "unixsock plugin".
SEE ALSO
       collectd.conf(5), collectd-email(5), collectd-exec(5),
       collectd-perl(5), collectd-snmp(5), collectd-unixsock(5), types.db(5),
       <http://collectd.org/>;
AUTHOR
       Florian Forster <octo AT collectd.org>
5.11.0.94.g41b1e33                2020-07-20                       COLLECTD(1)