+=over 4
+
+=item B<DataDir> I<Directory>
+
+Set the directory to store RRD files under. By default RRD files are generated
+beneath the daemon's working directory, i.e. the B<BaseDir>.
+
+=item B<CreateFilesAsync> B<false>|B<true>
+
+When enabled, new RRD files are enabled asynchronously, using a separate thread
+that runs in the background. This prevents writes to block, which is a problem
+especially when many hundreds of files need to be created at once. However,
+since the purpose of creating the files asynchronously is I<not> to block until
+the file is available, values before the file is available will be discarded.
+When disabled (the default) files are created synchronously, blocking for a
+short while, while the file is being written.
+
+=item B<StepSize> I<Seconds>
+
+B<Force> the stepsize of newly created RRD-files. Ideally (and per default)
+this setting is unset and the stepsize is set to the interval in which the data
+is collected. Do not use this option unless you absolutely have to for some
+reason. Setting this option may cause problems with the C<snmp plugin>, the
+C<exec plugin> or when the daemon is set up to receive data from other hosts.
+
+=item B<HeartBeat> I<Seconds>
+
+B<Force> the heartbeat of newly created RRD-files. This setting should be unset
+in which case the heartbeat is set to twice the B<StepSize> which should equal
+the interval in which data is collected. Do not set this option unless you have
+a very good reason to do so.
+
+=item B<RRARows> I<NumRows>
+
+The C<rrdtool plugin> calculates the number of PDPs per CDP based on the
+B<StepSize>, this setting and a timespan. This plugin creates RRD-files with
+three times five RRAs, i.e. five RRAs with the CFs B<MIN>, B<AVERAGE>, and
+B<MAX>. The five RRAs are optimized for graphs covering one hour, one day, one
+week, one month, and one year.
+
+So for each timespan, it calculates how many PDPs need to be consolidated into
+one CDP by calculating:
+ number of PDPs = timespan / (stepsize * rrarows)
+
+Bottom line is, set this no smaller than the width of you graphs in pixels. The
+default is 1200.
+
+=item B<RRATimespan> I<Seconds>
+
+Adds an RRA-timespan, given in seconds. Use this option multiple times to have
+more then one RRA. If this option is never used, the built-in default of (3600,
+86400, 604800, 2678400, 31622400) is used.
+
+For more information on how RRA-sizes are calculated see B<RRARows> above.
+
+=item B<XFF> I<Factor>
+
+Set the "XFiles Factor". The default is 0.1. If unsure, don't set this option.
+I<Factor> must be in the range C<[0.0-1.0)>, i.e. between zero (inclusive) and
+one (exclusive).
+
+=item B<CacheFlush> I<Seconds>
+
+When the C<rrdtool> plugin uses a cache (by setting B<CacheTimeout>, see below)
+it writes all values for a certain RRD-file if the oldest value is older than
+(or equal to) the number of seconds specified. If some RRD-file is not updated
+anymore for some reason (the computer was shut down, the network is broken,
+etc.) some values may still be in the cache. If B<CacheFlush> is set, then the
+entire cache is searched for entries older than B<CacheTimeout> seconds and
+written to disk every I<Seconds> seconds. Since this is kind of expensive and
+does nothing under normal circumstances, this value should not be too small.
+900 seconds might be a good value, though setting this to 7200 seconds doesn't
+normally do much harm either.
+
+=item B<CacheTimeout> I<Seconds>
+
+If this option is set to a value greater than zero, the C<rrdtool plugin> will
+save values in a cache, as described above. Writing multiple values at once
+reduces IO-operations and thus lessens the load produced by updating the files.
+The trade off is that the graphs kind of "drag behind" and that more memory is
+used.
+
+=item B<WritesPerSecond> I<Updates>
+
+When collecting many statistics with collectd and the C<rrdtool> plugin, you
+will run serious performance problems. The B<CacheFlush> setting and the
+internal update queue assert that collectd continues to work just fine even
+under heavy load, but the system may become very unresponsive and slow. This is
+a problem especially if you create graphs from the RRD files on the same
+machine, for example using the C<graph.cgi> script included in the
+C<contrib/collection3/> directory.
+
+This setting is designed for very large setups. Setting this option to a value
+between 25 and 80 updates per second, depending on your hardware, will leave
+the server responsive enough to draw graphs even while all the cached values