+=encoding UTF-8
+
=head1 NAME
collectd - System statistics collection daemon
Test the configuration only. The program immediately exits after parsing the
config file. A return code not equal to zero indicates an error.
+=item B<-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.
+
=item B<-P> I<E<lt>pid-fileE<gt>>
-Specify an alternative pid file. This overwrites any settings in the config
+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 B<PIDFile>
config-option.
+=item B<-B>
+
+If set, collectd will I<not> try to create its base directory. If the base
+directory does not exist, it will exit rather than trying to create the
+directory.
+
=item B<-f>
Don't fork to the background. I<collectd> will also B<not> close standard file
descriptors, detach from the session nor write a pid file. This is mainly
-thought for 'supervisioning' init replacements such as I<runit>.
+thought for 'supervising' init replacements such as I<runit>. If using
+I<upstart> or I<systemd> though, starting with version 5.5.0 I<collectd> is
+able to notify these two init replacements, and B<does> require forking to the
+background for process supervision. The F<contrib/> directory has sample
+I<upstart> and I<systemd> configuration files.
=item B<-h>
=head1 PLUGINS
-As noted above, the real power of collectd lies within it's plugins. A
+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
F<README> file that is distributed with the sourcecode. If you're using a
package it's a good bet to search somewhere near F</usr/share/doc/collectd>.
=over 4
-=item
+=item *
-Input plugins are queried periodically. They somehow aquire the current value
+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 C<cpu plugin>
reads the current cpu-counters of time spent in the various modes (user,
system, nice, ...) and dispatches these counters to the daemon.
-=item
+=item *
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
C<network plugin>, for example, is able to send (i.E<nbsp>e. "write") B<and>
receive (i.E<nbsp>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 if
+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
provide information about issues and significant situations to the user.
Several loglevels let you suppress uninteresting messages.
+Starting with version C<4.3.0> collectd has support for B<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
+L<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 L<collectd-email(5)>, L<collectd-exec(5)>,
-L<collectd-perl(5)>, and L<collectd-unixsock(5)>
+L<collectd-perl(5)>, L<collectd-snmp(5)>, and L<collectd-unixsock(5)>
+
+=head1 SIGNALS
+
+B<collectd> accepts the following signals:
+
+=over 4
+
+=item B<SIGINT>, B<SIGTERM>
+
+These signals cause B<collectd> to shut down all plugins and terminate.
+
+=item B<SIGUSR1>
+
+This signal causes B<collectd> to signal all plugins to flush data from
+internal caches. E.E<nbsp>g. the C<rrdtool plugin> will write all pending data
+to the RRD files. This is the same as using the C<FLUSH -1> command of the
+C<unixsock plugin>.
+
+=back
=head1 SEE ALSO
L<collectd-email(5)>,
L<collectd-exec(5)>,
L<collectd-perl(5)>,
+L<collectd-snmp(5)>,
L<collectd-unixsock(5)>,
+L<types.db(5)>,
L<http://collectd.org/>
=head1 AUTHOR
-Florian Forster E<lt>octo@verplant.orgE<gt>
+Florian Forster E<lt>octo@collectd.orgE<gt>
=cut
projects / collectd.git / blobdiff