=item
+Apache server stats (I<apache>)
+
+=item
+
+Apple hardware sensors (I<apple_sensors>, Darwin only)
+
+=item
+
Battery status (I<battery>)
=item
System ressources used by VServers (I<vserver>)
+=item
+
+Wireless network stats (I<wireless>)
+
=back
=head1 OPTIONS
written in RRD files that reside in I<DataDir>. This is the default mode when
collectd is linked against C<librrd>.
-The other two modes, B<client mode> and B<server mode>, are used to send data
-over a network and receive it again.
+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 it's results
+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.
+similar tool is installed and an "cpu governor" (that's kernel module) is
+loaded.
=head2 mysql
=head1 RRD FILES
-The RRD files are created automatically with the following RRAs:
-
- RRA:AVERAGE:0.0:1:1500
- RRA:AVERAGE:0.2:6:1500
- RRA:AVERAGE:0.1:180:1680
- RRA:AVERAGE:0.1:2160:1520
- RRA:MIN:0.0:1:1500
- RRA:MIN:0.2:6:1500
- RRA:MIN:0.1:180:1680
- RRA:MIN:0.1:2160:1520
- RRA:MAX:0.0:1:1500
- RRA:MAX:0.2:6:1500
- RRA:MAX:0.1:180:1680
- RRA:MAX:0.1:2160:1520
+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 seconds ! 1500 ! 4 hours
- 6 | 1 minute | 1500 | 25 hours
- 180 | 30 minutes | 1680 | 35 days
- 2160 | 6 hours | 1520 | 380 days
+ 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: