+default) counter values are stored as is, i.e. as an increasing integer number.
+
+=item B<BufferSize> I<Bytes>
+
+Sets the send buffer size to I<Bytes>. By increasing this buffer, less HTTP
+requests will be generated, but more metrics will be batched / metrics are
+cached for longer before being sent, introducing additional delay until they
+are available on the server side. I<Bytes> must be at least 1024 and cannot
+exceed the size of an C<int>, i.e. 2E<nbsp>GByte.
+Defaults to C<4096>.
+
+=back
+
+=head2 Plugin C<write_kafka>
+
+The I<write_kafka plugin> will send values to a I<Kafka> topic, a distributed
+queue.
+Synopsis:
+
+ <Plugin "write_kafka">
+ Property "metadata.broker.list" "broker1:9092,broker2:9092"
+ <Topic "collectd">
+ Format JSON
+ </Topic>
+ </Plugin>
+
+The following options are understood by the I<write_kafka plugin>:
+
+=over 4
+
+=item E<lt>B<Topic> I<Name>E<gt>
+
+The plugin's configuration consists of one or more B<Topic> blocks. Each block
+is given a unique I<Name> and specifies one kafka producer.
+Inside the B<Topic> block, the following per-topic options are
+understood:
+
+=over 4
+
+=item B<Property> I<String> I<String>
+
+Configure the named property for the current topic. Properties are
+forwarded to the kafka producer library B<librdkafka>.
+
+=item B<Key> I<String>
+
+Use the specified string as a partioning key for the topic. Kafka breaks
+topic into partitions and guarantees that for a given topology, the same
+consumer will be used for a specific key. The special (case insensitive)
+string B<Random> can be used to specify that an arbitrary partition should
+be used.
+
+=item B<Format> B<Command>|B<JSON>|B<Graphite>
+
+Selects the format in which messages are sent to the broker. If set to
+B<Command> (the default), values are sent as C<PUTVAL> commands which are
+identical to the syntax used by the I<Exec> and I<UnixSock plugins>.
+
+If set to B<JSON>, the values are encoded in the I<JavaScript Object Notation>,
+an easy and straight forward exchange format.
+
+If set to B<Graphite>, values are encoded in the I<Graphite> format, which is
+C<E<lt>metricE<gt> E<lt>valueE<gt> E<lt>timestampE<gt>\n>.
+
+=item B<StoreRates> B<true>|B<false>
+
+Determines whether or not C<COUNTER>, C<DERIVE> and C<ABSOLUTE> data sources
+are converted to a I<rate> (i.e. a C<GAUGE> value). If set to B<false> (the
+default), no conversion is performed. Otherwise the conversion is performed
+using the internal value cache.
+
+Please note that currently this option is only used if the B<Format> option has
+been set to B<JSON>.
+
+=item B<GraphitePrefix> (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
+C<E<lt>prefixE<gt>E<lt>hostE<gt>E<lt>postfixE<gt>E<lt>pluginE<gt>E<lt>typeE<gt>E<lt>nameE<gt>>
+
+=item B<GraphitePostfix> (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
+C<E<lt>prefixE<gt>E<lt>hostE<gt>E<lt>postfixE<gt>E<lt>pluginE<gt>E<lt>typeE<gt>E<lt>nameE<gt>>
+
+=item B<GraphiteEscapeChar> (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 C<_> (I<Underscore>).
+
+=item B<GraphiteSeparateInstances> B<false>|B<true>
+
+If set to B<true>, the plugin instance and type instance will be in their own
+path component, for example C<host.cpu.0.cpu.idle>. If set to B<false> (the
+default), the plugin and plugin instance (and likewise the type and type
+instance) are put into one component, for example C<host.cpu-0.cpu-idle>.
+
+=item B<StoreRates> B<true>|B<false>
+
+If set to B<true> (the default), convert counter values to rates. If set to
+B<false> counter values are stored as is, i.e. as an increasing integer number.
+
+This will be reflected in the C<ds_type> tag: If B<StoreRates> is enabled,
+converted values will have "rate" appended to the data source type, e.g.
+C<ds_type:derive:rate>.
+
+=back
+
+=item B<Property> I<String> I<String>
+
+Configure the kafka producer through properties, you almost always will
+want to set B<metadata.broker.list> to your Kafka broker list.
+
+=back
+
+=head2 Plugin C<write_riemann>
+
+The I<write_riemann plugin> will send values to I<Riemann>, a powerful stream
+aggregation and monitoring system. The plugin sends I<Protobuf> encoded data to
+I<Riemann> using UDP packets.
+
+Synopsis:
+
+ <Plugin "write_riemann">
+ <Node "example">
+ Host "localhost"
+ Port "5555"
+ Protocol UDP
+ StoreRates true
+ AlwaysAppendDS false
+ TTLFactor 2.0
+ </Node>
+ Tag "foobar"
+ Attribute "foo" "bar"
+ </Plugin>
+
+The following options are understood by the I<write_riemann plugin>:
+
+=over 4
+
+=item E<lt>B<Node> I<Name>E<gt>
+
+The plugin's configuration consists of one or more B<Node> blocks. Each block
+is given a unique I<Name> and specifies one connection to an instance of
+I<Riemann>. Indise the B<Node> block, the following per-connection options are
+understood:
+
+=over 4
+
+=item B<Host> I<Address>
+
+Hostname or address to connect to. Defaults to C<localhost>.
+
+=item B<Port> I<Service>
+
+Service name or port number to connect to. Defaults to C<5555>.
+
+=item B<Protocol> B<UDP>|B<TCP>
+
+Specify the protocol to use when communicating with I<Riemann>. Defaults to
+B<UDP>.
+
+=item B<StoreRates> B<true>|B<false>
+
+If set to B<true> (the default), convert counter values to rates. If set to
+B<false> counter values are stored as is, i.e. as an increasing integer number.
+
+This will be reflected in the C<ds_type> tag: If B<StoreRates> is enabled,
+converted values will have "rate" appended to the data source type, e.g.
+C<ds_type:derive:rate>.
+
+=item B<AlwaysAppendDS> B<false>|B<true>
+
+If set the B<true>, append the name of the I<Data Source> (DS) to the
+"service", i.e. the field that, together with the "host" field, uniquely
+identifies a metric in I<Riemann>. If set to B<false> (the default), this is
+only done when there is more than one DS.
+
+=item B<TTLFactor> I<Factor>
+
+I<Riemann> events have a I<Time to Live> (TTL) which specifies how long each
+event is considered active. I<collectd> populates this field based on the
+metrics interval setting. This setting controls the factor with which the
+interval is multiplied to set the TTL. The default value is B<2.0>. Unless you
+know exactly what you're doing, you should only increase this setting from its
+default value.
+
+=item B<Notifications> B<false>|B<true>
+
+If set to B<true>, create riemann events for notifications. This is B<true>
+by default. When processing thresholds from write_riemann, it might prove
+useful to avoid getting notification events.
+
+=item B<CheckThresholds> B<false>|B<true>
+
+If set to B<true>, attach state to events based on thresholds defined
+in the B<Threshold> plugin. Defaults to B<false>.
+
+=item B<EventServicePrefix> I<String>
+
+Add the given string as a prefix to the event service name.
+If B<EventServicePrefix> not set or set to an empty string (""),
+no prefix will be used.
+
+=back
+
+=item B<Tag> I<String>
+
+Add the given string as an additional tag to the metric being sent to
+I<Riemann>.
+
+=item B<Attribute> I<String> I<String>
+
+Consider the two given strings to be the key and value of an additional
+attribute for each metric being sent out to I<Riemann>.