either C<perl> or C<python>, the default is changed to enabled in order to keep
the average user from ever having to deal with this low level linking stuff.
+=item B<Interval> I<Seconds>
+
+Sets a plugin-specific interval for collecting metrics. This overrides the
+global B<Interval> setting. If a plugin provides own support for specifying an
+interval, that setting will take precedence.
+
=back
=item B<Include> I<Path>
require external configuration, too. The C<apache plugin>, for example,
required C<mod_status> to be configured in the webserver you're going to
collect data from. These plugins are listed below as well, even if they don't
-require any configuration within collectd's configfile.
+require any configuration within collectd's configuration file.
A list of all plugins and a short summary for each plugin can be found in the
F<README> file shipped with the sourcecode and hopefully binary packets as
well.
+=head2 Plugin C<aggregation>
+
+The I<Aggregation plugin> makes it possible to aggregate several values into
+one using aggregation functions such as I<sum>, I<average>, I<min> and I<max>.
+This can be put to a wide variety of uses, e.g. average and total CPU
+statistics for your entire fleet.
+
+The grouping is powerful but, as with many powerful tools, may be a bit
+difficult to wrap your head around. The grouping will therefore be
+demonstrated using an example: The average and sum of the CPU usage across
+all CPUs of each host is to be calculated.
+
+To select all the affected values for our example, set C<Plugin cpu> and
+C<Type cpu>. The other values are left unspecified, meaning "all values". The
+I<Host>, I<Plugin>, I<PluginInstance>, I<Type> and I<TypeInstance> options
+work as if they were specified in the C<WHERE> clause of an C<SELECT> SQL
+statement.
+
+ Plugin "cpu"
+ Type "cpu"
+
+Although the I<Host>, I<PluginInstance> (CPU number, i.e. 0, 1, 2, ...) and
+I<TypeInstance> (idle, user, system, ...) fields are left unspecified in the
+example, the intention is to have a new value for each host / type instance
+pair. This is achieved by "grouping" the values using the C<GroupBy> option.
+It can be specified multiple times to group by more than one field.
+
+ GroupBy "Host"
+ GroupBy "TypeInstance"
+
+We do neither specify nor group by I<plugin instance> (the CPU number), so all
+metrics that differ in the CPU number only will be aggregated. Each
+aggregation needs I<at least one> such field, otherwise no aggregation would
+take place.
+
+The full example configuration looks like this:
+
+ <Plugin "aggregation">
+ <Aggregation>
+ Plugin "cpu"
+ Type "cpu"
+
+ GroupBy "Host"
+ GroupBy "TypeInstance"
+
+ CalculateSum true
+ CalculateAverage true
+ </Aggregation>
+ </Plugin>
+
+There are a couple of limitations you should be aware of:
+
+=over 4
+
+=item
+
+The I<Type> cannot be left unspecified, because it is not reasonable to add
+apples to oranges. Also, the internal lookup structure won't work if you try
+to group by type.
+
+=item
+
+There must be at least one unspecified, ungrouped field. Otherwise nothing
+will be aggregated.
+
+=back
+
+As you can see in the example above, each aggregation has its own
+B<Aggregation> block. You can have multiple aggregation blocks and aggregation
+blocks may match the same values, i.e. one value list can update multiple
+aggregations. The following options are valid inside B<Aggregation> blocks:
+
+=over 4
+
+=item B<Host> I<Host>
+
+=item B<Plugin> I<Plugin>
+
+=item B<PluginInstance> I<PluginInstance>
+
+=item B<Type> I<Type>
+
+=item B<TypeInstance> I<TypeInstance>
+
+Selects the value lists to be added to this aggregation. B<Type> must be a
+valid data set name, see L<types.db(5)> for details.
+
+=item B<GroupBy> B<Host>|B<Plugin>|B<PluginInstance>|B<TypeInstance>
+
+Group valued by the specified field. The B<GroupBy> option may be repeated to
+group by multiple fields.
+
+=item B<CalculateNum> B<true>|B<false>
+
+=item B<CalculateSum> B<true>|B<false>
+
+=item B<CalculateAverage> B<true>|B<false>
+
+=item B<CalculateMinimum> B<true>|B<false>
+
+=item B<CalculateMaximum> B<true>|B<false>
+
+=item B<CalculateStddev> B<true>|B<false>
+
+Boolean options for enabling calculation of the number of value lists, their
+sum, average, minimum, maximum andE<nbsp>/ or standard deviation. All options
+are disabled by default.
+
+=back
+
=head2 Plugin C<amqp>
The I<AMQMP plugin> can be used to communicate with other instances of
# Persistent false
# Format "command"
# StoreRates false
+ # GraphitePrefix "collectd."
+ # GraphiteEscapeChar "_"
</Publish>
# Receive values from an AMQP broker
an easy and straight forward exchange format. The C<Content-Type> header field
will be set to C<application/json>.
+If set to B<Graphite>, values are encoded in the I<Graphite> format, which is
+"<metric> <value> <timestamp>\n". The C<Content-Type> header field will be set to
+C<text/graphite>.
+
A subscribing client I<should> use the C<Content-Type> header field to
determine how to decode the values. Currently, the I<AMQP plugin> itself can
only decode the B<Command> format.
Please note that currently this option is only used if the B<Format> option has
been set to B<JSON>.
+=item B<GraphitePrefix> (Publish and B<Format>=I<Graphite> only)
+
+A prefix can be added in the metric name when outputting in the I<Graphite> format.
+It's added before the I<Host> name.
+Metric name will be "<prefix><host><postfix><plugin><type><name>"
+
+=item B<GraphitePostfix> (Publish and B<Format>=I<Graphite> only)
+
+A postfix can be added in the metric name when outputting in the I<Graphite> format.
+It's added after the I<Host> name.
+Metric name will be "<prefix><host><postfix><plugin><type><name>"
+
+=item B<GraphiteEscapeChar> (Publish and B<Format>=I<Graphite> only)
+
+Specify a character to replace dots (.) in the host part of the metric name.
+In I<Graphite> metric name, dots are used as separators between different
+metric parts (host, plugin, type).
+Default is "_" (I<Underscore>).
+
=back
=head2 Plugin C<apache>
about cache utilization, memory and bandwidth used.
L<http://www.danga.com/memcached/>
+ <Plugin "memcached">
+ <Instance "name">
+ Host "memcache.example.com"
+ Port 11211
+ </Instance>
+ </Plugin>
+
+The plugin configuration consists of one or more B<Instance> blocks which
+specify one I<memcached> connection each. Within the B<Instance> blocks, the
+following options are allowed:
+
=over 4
=item B<Host> I<Hostname>
TCP-Port to connect to. Defaults to B<11211>.
+=item B<Socket> I<Path>
+
+Connect to I<memcached> using the UNIX domain socket at I<Path>. If this
+setting is given, the B<Host> and B<Port> settings are ignored.
+
=back
=head2 Plugin C<modbus>
lookups. The default is to do reverse lookups to preserve backwards
compatibility, though.
+=item B<IncludeUnitID> B<true>|B<false>
+
+When a peer is a refclock, include the unit ID in the I<type instance>.
+Defaults to B<false> for backward compatibility.
+
+If two refclock peers use the same driver and this is B<false>, the plugin will
+try to write simultaneous measurements from both to the same type instance.
+This will result in error messages in the log and only one set of measurements
+making it through.
+
=back
=head2 Plugin C<nut>
Defines the "database alias" or "service name" to connect to. Usually, these
names are defined in the file named C<$ORACLE_HOME/network/admin/tnsnames.ora>.
+=item B<Host> I<Host>
+
+Hostname to use when dispatching values for this database. Defaults to using
+the global hostname of the I<collectd> instance.
+
=item B<Username> I<Username>
Username used for authentication.
The name of the database of the current connection.
+=item I<instance>
+
+The name of the database plugin instance. See the B<Instance> option of the
+database specification below for details.
+
=item I<username>
The username used to connect to the database.
Specify whether to use an SSL connection when contacting the server. The
following modes are supported:
+=item B<Instance> I<name>
+
+Specify the plugin instance name that should be used instead of the database
+name (which is the default, if this option has not been specified). This
+allows to query multiple databases of the same name on the same host (e.g.
+when running multiple database server versions in parallel).
+
=over 4
=item I<disable>
connections. Either a service name of a port number may be given. Please note
that numerical port numbers must be given as a string, too.
+=item B<Password> I<Password>
+
+Use I<Password> to authenticate when connecting to I<Redis>.
+
=item B<Timeout> I<Timeout in miliseconds>
The B<Timeout> option set the socket timeout for node response. Since the Redis
locally, or B<DataDir> is set to a relative path, this will not work as
expected. Default is B<true>.
+=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).
+
=back
=head2 Plugin C<rrdtool>
=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>
This option is only available if the I<Swap plugin> can read C</proc/swaps>
(under Linux) or use the L<swapctl(2)> mechanism (under I<Solaris>).
+=item B<ReportBytes> B<false>|B<true>
+
+When enabled, the I<swap I/O> is reported in bytes. When disabled, the default,
+I<swap I/O> is reported in pages. This option is available under Linux only.
+
=back
=head2 Plugin C<syslog>