=item
+Apache server stats (I<apache>)
+
+=item
+
+Apple hardware sensors (I<apple_sensors>, Darwin only)
+
+=item
+
Battery status (I<battery>)
=item
Number of users logged into the system (I<users>)
+=item
+
+System ressources used by VServers (I<vserver>)
+
+=item
+
+Wireless network stats (I<wireless>)
+
=back
=head1 OPTIONS
=back
-=head1 RRD FILES
+=head1 MODES
+
+collectd can operate in three different operating modes. The modes are
+described below.
+
+The simplest mode is the so called B<local mode>. Data is collected locally and
+written in RRD files that reside in I<DataDir>. This is the default mode when
+collectd is linked against C<librrd>.
+
+The other modes, B<client mode> and B<server mode>, are used to send data over
+a network and receive it again.
+
+In B<client mode> the daemon collects the data locally and sends its results
+to one or more network addresses. No RRD files are written in this case. This
+is the only mode available if collectd is not linked against C<librrd>.
+
+If started in B<server mode> the daemon will listen on one or more interfaces
+and write the data it receives to RRD files. No data is collected locally.
+
+In the last mode, B<log mode>, data is collected locally and written in
+text files that reside in I<DataDir>.
+
+Please refer to L<collectd.conf(5)> for the configuration options and default
+values.
+
+=head1 SPECIAL PLUGINS
+
+=head2 apache
+
+This module connects to an Apache webserver and expects the output produced by
+B<mod_status.c>. If requires B<libcurl> to set up the HTTP connection and issue
+the request(s). The following is a sample config for the Apache webserver. The
+use of C<ExtendedStatus on> is mandatory.
+
+ ExtendedStatus on
+ <IfModule mod_status.c>
+ <Location /mod_status>
+ SetHandler server-status
+ </Location>
+ </IfModule>
+
+This plugin requires further configuration. Please read L<collectd.conf(5)>.
+
+=head2 cpufreq
+
+This module reads F</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 B<cpufreqd> (L<http://cpufreqd.sourceforge.net/>) or a
+similar tool is installed and an "cpu governor" (that's kernel module) is
+loaded.
+
+=head2 mysql
+
+Requires B<mysqlclient> to be installed. It connects to the database 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 syslog will
+contain loud complaints in case anything goes wrong.
+
+This plugin issues C<SHOW STATUS> and evaluates C<Bytes_{received,sent}>,
+C<Com_*> and C<Handler_*> which correspond to F<traffic-mysql.rrd>,
+F<mysql_commands-*.rrd> and F<mysql_handler-*.rrd>. Also, the values of
+C<Qcache_*> are put in F<mysql_qcache.rrd> and values of C<Threads_*> are put
+in F<mysql_threads.rrd>. Please refer to the B<MySQL reference manual>,
+I<5.2.4. Server Status Variables> for an explanation of these values.
+
+=head2 sensors
+
+The B<sensors> module 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 F</etc/sensors.conf>. Read
+L<sensors.conf(5)> for details.
+
+The B<lm_sensors> homepage can be found at
+L<http://secure.netroedge.com/~lm78/>.
+
+=head2 hddtemp
+
+To get values from B<hddtemp> collectd connects to B<localhost> (127.0.0.1),
+port B<7634/tcp>. The B<Host> and B<Port> options can be used to change these
+default values. See L<collectd.conf(5)> for details. C<hddtemp> has to be
+running to work correctly. If C<hddtemp> is not running timeouts may appear
+which may interfere with other statistics..
+
+The B<hddtemp> homepage can be found at
+L<http://www.guzu.net/linux/hddtemp.php>.
+
+=head2 vserver
-The RRD files are created automatically with the following RRAs:
+B<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
+B<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.
- RRA:AVERAGE:0.2:6:1500
- RRA:AVERAGE:0.1:180:1680
- RRA:AVERAGE:0.1:2160:1520
- RRA:MIN:0.2:6:1500
- RRA:MIN:0.1:180:1680
- RRA:MIN:0.1:2160:1520
- RRA:MAX:0.2:6:1500
- RRA:MAX:0.1:180:1680
- RRA:MAX:0.1:2160:1520
+The B<VServer> homepage can be found at L<http://linux-vserver.org/>.
-Since collectd uses a 10 second I<step> the RRAs contain the following
-timespans:
+=head1 RRD FILES
- Resolution | Data points | Timespan
- -----------+-------------+----------
- 60 seconds | 1500 | 25 hours
- 30 minutes | 1680 | 35 days
- 6 hours | 1520 | 380 days
+The RRD files are created automatically. The size of the RRAs depend on the
+compile time settings of I<step> and I<width>. With the default values (I<step>
+= B<10>, I<width> = B<1200>) the following RRAs are created:
+
+ RRA:AVERAGE:0.1:1:8640
+ RRA:AVERAGE:0.1:50:1210
+ RRA:AVERAGE:0.1:223:1202
+ RRA:AVERAGE:0.1:2635:1201
+ RRA:MIN:0.1:1:8640
+ RRA:MIN:0.1:50:1210
+ RRA:MIN:0.1:223:1202
+ RRA:MIN:0.1:2635:1201
+ RRA:MAX:0.1:1:8640
+ RRA:MAX:0.1:50:1210
+ RRA:MAX:0.1:223:1202
+ RRA:MAX:0.1:2635:1201
+
+By default collectd uses a 10 second I<step>. Thus the RRAs contain the
+following timespans. If you've changed the I<step> at compile time you will
+have calculate resolution and timespan yourself.
+
+ PDP per CDP | Resolution | Data points | Timespan
+ ------------+--------------+-------------+---------
+ 1 | 10.0 seconds ! 8640 ! 1 day
+ 50 | 8.3 minutes | 1210 | 1 week
+ 223 | 37.2 minutes | 1202 | 1 month
+ 2635 | 7.3 hours | 1201 | 1 year
The DS'es depend on the module creating the RRD files:
DS:users:GAUGE:25:0:65535
-=back
-
-=head1 MODES
-
-By default collectd starts in the so called I<local mode> which is not very
-interesting. It collects data and writes it into RRD files in
-F</var/lib/collectd>. There's nothing special so I won't discuss that in more
-detail..
-
-Please be aware that B<client-, local- and server-mode are mutual exclusive>. A
-later declaration overrides earlier ones. I<collectd -l -c -s> will start in
-server-mode. If you want statistics of the server too you will have to start a
-client process as well.
-
-Starting with version 3 collectd may send data over a network. As common with
-network stuff there are two modes: A I<sender> and a I<listener>. Since one
-usually has many senders and only a few listeners the sender is also called
-I<client> (using the option B<-c>) and the listener is called I<server> (using
-the option B<-s>).
-
-Communication happends using the (IPv4) multicast group B<239.192.74.66> and
-packets sent to the port B<25826/udp>. Every ten seconds the I<client> queries
-all the modules and sends the collected data to the multicast group. The
-I<server> subscribes to the multicast group upon startup and then waits for
-incoming packets. As it receives the packets it checks wether it has the
-neccessary module and, if found, writes the data to an RRD file, creating
-directories and files as needed.
-
-The multicast group used is within the I<Organization Local Scope> as defined
-by L<RFC2365>. Addresses within that space are meant to be routed within an AS
-but not to the outside. However collectd cannot control this and won't try. So
-it's totally up to you to secure your net.
-
-The UDP port used has been checked to not be assigned by the IANA.
-
-On multi-homed machines you may need to add a route to the multicast net
-(B<224.0.0.0/4>) if multicast packages take the wrong interface. The listener
-on the other hand listens on B<all> interfaces.
-
-=head1 SPECIAL PLUGINS
+=item VServer load (F<vserver-I<E<lt>xidE<gt>>/load.rrd>)
-=head2 cpufreq
-
-This module reads F</sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq> (for
-the first CPU installed) to get the current CPU frequency. If this file does
-not exist make sure B<cpufreqd> (L<http://cpufreqd.sourceforge.net/>) or a
-similar tool is installed.
+ DS:shortterm:GAUGE:25:0:100
+ DS:midterm:GAUGE:25:0:100
+ DS:longterm:GAUGE:25:0:100
-=head2 mysql
+=item VServer threads (F<vserver-I<E<lt>xidE<gt>>/threads.rrd>)
-Requires B<mysqlclient> to be installed. It connects to the database 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 syslog will
-contain loud complaints in case anything goes wrong.
+ DS:total:GAUGE:25:0:65535
+ DS:running:GAUGE:25:0:65535
+ DS:uninterruptible:GAUGE:25:0:65535
+ DS:onhold:GAUGE:25:0:65535
-This plugin issues C<SHOW STATUS> and evaluates C<Bytes_{received,sent}>,
-C<Com_*> and C<Handler_*> which correspond to F<traffic-mysql.rrd>,
-F<mysql_commands-*.rrd> and F<mysql_handler-*.rrd>. Also, the values of
-C<Qcache_*> are put in F<mysql_qcache.rrd> and values of C<Threads_*> are put
-in F<mysql_threads.rrd>. Please refer to the B<MySQL reference manual>,
-I<5.2.4. Server Status Variables> for an explanation of these values.
+=item VServer network traffic (F<vserver-I<E<lt>xidE<gt>>/traffic-I<E<lt>nameE<gt>>.rrd>)
-=head2 sensors
+ DS:incoming:COUNTER:25:0:9223372036854775807
+ DS:outgoing:COUNTER:25:0:9223372036854775807
+ DS:failed:COUNTER:25:0:9223372036854775807
-The B<sensors> module 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 F</etc/sensors.conf>. Read
-L<sensors.conf(5)> for details.
+=item VServer processes (F<vserver-I<E<lt>xidE<gt>>/vs_processes.rrd>)
-The B<lm_sensors> homepage can be found at
-L<http://secure.netroedge.com/~lm78/>.
+ DS:total:GAUGE:25:0:65535
-=head2 hddtemp
+=item VServer memory usage (F<vserver-I<E<lt>xidE<gt>>/vs_memory.rrd>)
-To get values from B<hddtemp> collectd connects to B<localhost> (127.0.0.1),
-port B<7634/tcp>. hddtemp has to be running to work correctly. If hddtemp is
-not running timeouts may appear which may interfere with other statistics..
+ DS:vm:GAUGE:25:0:9223372036854775807
+ DS:vml:GAUGE:25:0:9223372036854775807
+ DS:rss:GAUGE:25:0:9223372036854775807
+ DS:anon:GAUGE:25:0:9223372036854775807
-The B<hddtemp> homepage can be found at
-L<http://www.guzu.net/linux/hddtemp.php>.
+=back
=head1 SEE ALSO