Merge branch 'master' into ff/rrdcached

[collectd.git] / src / collectd.conf.pod

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 51d6c2e..9f0e34a 100644 (file)
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -1044,6 +1044,13 @@ B<EXPERIMENTAL!> See notes below.
 The C<onewire> plugin uses the B<owcapi> library from the B<owfs> project
 L<http://owfs.org/> to read sensors connected via the onewire bus.
 
+Currently only temperature sensors (sensors with the family code C<10>,
+e.E<nbsp>g. DS1820, DS18S20, DS1920) can be read. If you have other sensors you
+would like to have included, please send a sort request to the mailing list.
+
+Hubs (the DS2409 chips) are working, but read the note, why this plugin is
+experimental, below.
+
 =over 4
 
 =item B<Device> I<Device>
@@ -1493,6 +1500,56 @@ and minor and major pagefaults.
 
 =back
 
+=head2 Plugin C<rrdcached>
+
+The C<rrdcached> plugin uses the RRDTool accelerator daemon, L<rrdcached(1)>,
+to store values to RRD files in an efficient manner. The combination of the
+C<rrdcached> B<plugin> and the C<rrdcached> B<daemon> is very similar to the
+way the C<rrdtool> plugin works (see below). The added abstraction layer
+provides a number of benefits, though: Because the cache is not within
+C<collectd> anymore, it does not need to be flushed when C<collectd> is to be
+restarted. This results in much shorter (if any) gaps in graphs, especially
+under heavy load. Also, the C<rrdtool> command line utility is aware of the
+daemon so that it can flush values to disk automatically when needed. This
+allows to integrate automated flushing of values into graphing solutions much
+more easily.
+
+There are disadvantages, though: The daemon may reside on a different host, so
+it may not be possible for C<collectd> to create the appropriate RRD files
+anymore. And even if C<rrdcached> runs on the same host, it may run in a
+different base directory, so relative paths may do weird stuff if you're not
+careful.
+
+So the B<recommended configuration> is to let C<collectd> and C<rrdcached> run
+on the same host, communicating via a UNIX domain socket. The B<DataDir>
+setting should be set to an absolute path, so that a changed base directory
+does not result in RRD files being createdE<nbsp>/ expected in the wrong place.
+
+=over 4
+
+=item B<DaemonAddress> I<Address>
+
+Address of the daemon as understood by the C<rrdc_connect> function of the RRD
+library. See L<rrdcached(1)> for details. Example:
+
+  <Plugin "rrdcached">
+    DaemonAddress "unix:/var/run/rrdcached.sock"
+  </Plugin>
+
+=item B<DataDir> I<Directory>
+
+Set the base directory in which the RRD files reside. If this is a relative
+path, it is relative to the working base directory of the C<rrdcached> daemon!
+Use of an absolute path is recommended.
+
+=item B<CreateFiles> B<true>|B<false>
+
+Enables or disables the creation of RRD files. If the daemon is not running
+locally, or B<DataDir> is set to a relative path, this will not work as
+expected. Default is B<true>.
+
+=back
+
 =head2 Plugin C<rrdtool>
 
 You can use the settings B<StepSize>, B<HeartBeat>, B<RRARows>, and B<XFF> to
@@ -1666,7 +1723,7 @@ user using (extended) regular expressions, as described in L<regex(7)>.
       <Match>
        Regex "\\<R=local_user\\>"
        DSType "CounterInc"
-       Type "email_count"
+       Type "counter"
        Instance "local_user"
       </Match>
     </File>