Some Plugins may register own options. These options must be inclosed in a
C<Plugin>-Section. Which options exist depends on the plugin used:
+=head2 Plugin C<apache>
+
+=over 4
+
+=item B<URL> I<http://host/mod_status?auto>
+
+Sets the URL of the C<mod_status> output. This needs to be the output generated
+by C<ExtendedStatus on> and it needs to be the machine readable output
+generated by appending the C<?auto> argument.
+
+=item B<User> I<Username>
+
+Optional user name needed for authentication.
+
+=item B<Password> I<Password>
+
+Optional password needed for authentication.
+
+=back
+
=head2 Plugin C<hddtemp>
=over 4
=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: