X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Fcollectd.conf.pod;h=bee566cd1a991fa9c7f1fc51ec6834c4185a14db;hb=b4c8f3f762d666742c774ab3b45815e5a416e5da;hp=4541870b4ad530e28de01000b8713876cc2d9f91;hpb=d6ef3dad2f3dc9d7c35a9bbb563e52c3f0c1ec7c;p=collectd.git

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 4541870b..bee566cd 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -25,22 +25,32 @@ controls which plugins to load. These plugins ultimately define collectd's
 behavior.
 
 The syntax of this config file is similar to the config file of the famous
-B<Apache Webserver>. Each line contains either a key-value-pair or a
-section-start or -end. Empty lines and everything after the hash-symbol `#' is
-ignored. Values are either string, enclosed in double-quotes,
-(floating-point-)numbers or a boolean expression, i.E<nbsp>e. either B<true> or
-B<false>. String containing of only alphanumeric characters and underscores do
-not need to be quoted. Lines may be wrapped by using `\' as the last character
-before the newline. This allows long lines to be split into multiple lines.
-Quoted strings may be wrapped as well. However, those are treated special in
-that whitespace at the beginning of the following lines will be ignored, which
-allows for nicely indenting the wrapped lines.
-
-The configuration is read and processed in order, i.E<nbsp>e. from top to
-bottom. So the plugins are loaded in the order listed in this config file. It
-is a good idea to load any logging plugins first in order to catch messages
-from plugins during configuration. Also, the C<LoadPlugin> option B<must> occur
-B<before> the C<E<lt>Plugin ...E<gt>> block.
+I<Apache> webserver. Each line contains either an option (a key and a list of
+one or more values) or a section-start or -end. Empty lines and everything
+after a non-quoted hash-symbol (C<#>) is ignored. I<Keys> are unquoted
+strings, consisting only of alphanumeric characters and the underscore (C<_>)
+character. Keys are handled case insensitive by I<collectd> itself and all
+plugins included with it. I<Values> can either be an I<unquoted string>, a
+I<quoted string> (enclosed in double-quotes) a I<number> or a I<boolean>
+expression. I<Unquoted strings> consist of only alphanumeric characters and
+underscores (C<_>) and do not need to be quoted. I<Quoted strings> are
+enclosed in double quotes (C<">). You can use the backslash character (C<\>)
+to include double quotes as part of the string. I<Numbers> can be specified in
+decimal and floating point format (using a dot C<.> as decimal separator),
+hexadecimal when using the C<0x> prefix and octal with a leading zero (C<0>).
+I<Boolean> values are either B<true> or B<false>.
+
+Lines may be wrapped by using C<\> as the last character before the newline.
+This allows long lines to be split into multiple lines. Quoted strings may be
+wrapped as well. However, those are treated special in that whitespace at the
+beginning of the following lines will be ignored, which allows for nicely
+indenting the wrapped lines.
+
+The configuration is read and processed in order, i.e. from top to bottom. So
+the plugins are loaded in the order listed in this config file. It is a good
+idea to load any logging plugins first in order to catch messages from plugins
+during configuration. Also, the C<LoadPlugin> option B<must> occur B<before>
+the appropriate C<E<lt>Plugin ...E<gt>> block.
 
 =head1 GLOBAL OPTIONS
 
@@ -57,6 +67,37 @@ directory for the daemon.
 Loads the plugin I<Plugin>. There must be at least one such line or B<collectd>
 will be mostly useless.
 
+Starting with collectd 4.9, this may also be a block in which further options
+affecting the behavior of B<LoadPlugin> may be specified. The following
+options are allowed inside a B<LoadPlugin> block:
+
+  <LoadPlugin perl>
+    Globals true
+  </LoadPlugin>
+
+=over 4
+
+=item B<Globals> B<true|false>
+
+If enabled, collectd will export all global symbols of the plugin (and of all
+libraries loaded as dependencies of the plugin) and, thus, makes those symbols
+available for resolving unresolved symbols in subsequently loaded plugins if
+that is supported by your system.
+
+This is useful (or possibly even required), e.g., when loading a plugin that
+embeds some scripting language into the daemon (e.g. the I<Perl> and
+I<Python plugins>). Scripting languages usually provide means to load
+extensions written in C. Those extensions require symbols provided by the
+interpreter, which is loaded as a dependency of the respective collectd plugin.
+See the documentation of those plugins (e.g., L<collectd-perl(5)> or
+L<collectd-python(5)>) for details.
+
+By default, this is disabled. As a special exception, if the plugin name is
+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.
+
+=back
+
 =item B<Include> I<Path>
 
 If I<Path> points to a file, includes that file. If I<Path> points to a
@@ -102,6 +143,10 @@ Configures the interval in which to query the read plugins. Obviously smaller
 values lead to a higher system load produced by collectd, while higher values
 lead to more coarse statistics.
 
+B<Warning:> You should set this once and then never touch it again. If you do,
+I<you will have to delete all your RRD files> or know some serious RRDtool
+magic! (Assuming you're using the I<RRDtool> or I<RRDCacheD> plugin.)
+
 =item B<Timeout> I<Iterations>
 
 Consider a value list "missing" when no update has been read or received for
@@ -110,7 +155,7 @@ missing when no update has been received for twice the update interval. Since
 this setting uses iterations, the maximum allowed time without update depends
 on the I<Interval> information contained in each value list. This is used in
 the I<Threshold> configuration to dispatch notifications about missing values,
-see L<"THRESHOLD CONFIGURATION"> below.
+see L<collectd-threshold(5)> for details.
 
 =item B<ReadThreads> I<Num>
 
@@ -154,6 +199,143 @@ 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<amqp>
+
+The I<AMQMP plugin> can be used to communicate with other instances of
+I<collectd> or third party applications using an AMQP message broker. Values
+are sent to or received from the broker, which handles routing, queueing and
+possibly filtering or messages.
+
+ <Plugin "amqp">
+   # Send values to an AMQP broker
+   <Publish "some_name">
+     Host "localhost"
+     Port "5672"
+     VHost "/"
+     User "guest"
+     Password "guest"
+     Exchange "amq.fanout"
+ #   ExchangeType "fanout"
+ #   RoutingKey "collectd"
+ #   Persistent false
+ #   Format "command"
+ #   StoreRates false
+   </Publish>
+   
+   # Receive values from an AMQP broker
+   <Subscribe "some_name">
+     Host "localhost"
+     Port "5672"
+     VHost "/"
+     User "guest"
+     Password "guest"
+     Exchange "amq.fanout"
+ #   ExchangeType "fanout"
+ #   Queue "queue_name"
+ #   RoutingKey "collectd.#"
+   </Subscribe>
+ </Plugin>
+
+The plugin's configuration consists of a number of I<Publish> and I<Subscribe>
+blocks, which configure sending and receiving of values respectively. The two
+blocks are very similar, so unless otherwise noted, an option can be used in
+either block. The name given in the blocks starting tag is only used for
+reporting messages, but may be used to support I<flushing> of certain
+I<Publish> blocks in the future.
+
+=over 4
+
+=item B<Host> I<Host>
+
+Hostname or IP-address of the AMQP broker. Defaults to the default behavior of
+the underlying communications library, I<rabbitmq-c>, which is "localhost".
+
+=item B<Port> I<Port>
+
+Service name or port number on which the AMQP broker accepts connections. This
+argument must be a string, even if the numeric form is used. Defaults to
+"5672".
+
+=item B<VHost> I<VHost>
+
+Name of the I<virtual host> on the AMQP broker to use. Defaults to "/".
+
+=item B<User> I<User>
+
+=item B<Password> I<Password>
+
+Credentials used to authenticate to the AMQP broker. By default "guest"/"guest"
+is used.
+
+=item B<Exchange> I<Exchange>
+
+In I<Publish> blocks, this option specifies the I<exchange> to send values to.
+By default, "amq.fanout" will be used.
+
+In I<Subscribe> blocks this option is optional. If given, a I<binding> between
+the given exchange and the I<queue> is created, using the I<routing key> if
+configured. See the B<Queue> and B<RoutingKey> options below.
+
+=item B<ExchangeType> I<Type>
+
+If given, the plugin will try to create the configured I<exchange> with this
+I<type> after connecting. When in a I<Subscribe> block, the I<queue> will then
+be bound to this exchange.
+
+=item B<Queue> I<Queue> (Subscribe only)
+
+Configures the I<queue> name to subscribe to. If no queue name was configures
+explicitly, a unique queue name will be created by the broker.
+
+=item B<RoutingKey> I<Key>
+
+In I<Publish> blocks, this configures the routing key to set on all outgoing
+messages. If not given, the routing key will be computed from the I<identifier>
+of the value. The host, plugin, type and the two instances are concatenated
+together using dots as the separator and all containing dots replaced with
+slashes. For example "collectd.host/example/com.cpu.0.cpu.user". This makes it
+possible to receive only specific values using a "topic" exchange.
+
+In I<Subscribe> blocks, configures the I<routing key> used when creating a
+I<binding> between an I<exchange> and the I<queue>. The usual wildcards can be
+used to filter messages when using a "topic" exchange. If you're only
+interested in CPU statistics, you could use the routing key "collectd.*.cpu.#"
+for example.
+
+=item B<Persistent> B<true>|B<false> (Publish only)
+
+Selects the I<delivery method> to use. If set to B<true>, the I<persistent>
+mode will be used, i.e. delivery is guaranteed. If set to B<false> (the
+default), the I<transient> delivery mode will be used, i.e. messages may be
+lost due to high load, overflowing queues or similar issues.
+
+=item B<Format> B<Command>|B<JSON> (Publish only)
+
+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>. In this
+case, the C<Content-Type> header field will be set to C<text/collectd>.
+
+If set to B<JSON>, the values are encoded in the I<JavaScript Object Notation>,
+an easy and straight forward exchange format. The C<Content-Type> header field
+will be set to C<application/json>.
+
+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.
+
+=item B<StoreRates> B<true>|B<false> (Publish only)
+
+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>.
+
+=back
+
 =head2 Plugin C<apache>
 
 To configure the C<apache>-plugin you first need to configure the Apache
@@ -172,7 +354,25 @@ Since its C<mod_status> module is very similar to Apache's, B<lighttpd> is
 also supported. It introduces a new field, called C<BusyServers>, to count the
 number of currently connected clients. This field is also supported.
 
-The following options are accepted by the C<apache>-plugin:
+The configuration of the I<Apache> plugin consists of one or more
+C<E<lt>InstanceE<nbsp>/E<gt>> blocks. Each block requires one string argument
+as the instance name. For example:
+
+ <Plugin "apache">
+   <Instance "www1">
+     URL "http://www1.example.com/mod_status?auto"
+   </Instance>
+   <Instance "www2">
+     URL "http://www2.example.com/mod_status?auto"
+   </Instance>
+ </Plugin>
+
+The instance name will be used as the I<plugin instance>. To emulate the old
+(versionE<nbsp>4) behavior, you can use an empty string (""). In order for the
+plugin to work correctly, each instance name must be unique. This is not
+enforced by the plugin and it is your responsibility to ensure it.
+
+The following options are accepted within each I<Instance> block:
 
 =over 4
 
@@ -180,7 +380,7 @@ The following options are accepted by the C<apache>-plugin:
 
 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.
+generated by appending the C<?auto> argument. This option is I<mandatory>.
 
 =item B<User> I<Username>
 
@@ -549,22 +749,6 @@ runtime statistics module of CouchDB
     </URL>
   </Plugin>
 
-Another CouchDB example:
-The following example will collect the status values from each database:
-
-  <URL "http://localhost:5984/_all_dbs">
-    Instance "dbs"
-    <Key "*/doc_count">
-      Type "gauge"
-    </Key>
-    <Key "*/doc_del_count">
-      Type "counter"
-    </Key>
-    <Key "*/disk_size">
-      Type "bytes"
-    </Key>
-  </URL>
-
 In the B<Plugin> block, there may be one or more B<URL> blocks, each defining
 a URL to be fetched via HTTP (using libcurl) and one or more B<Key> blocks.
 The B<Key> string argument must be in a path format, which is used to collect a
@@ -649,7 +833,7 @@ The B<curl_xml plugin> uses B<libcurl> (L<http://curl.haxx.se/>) and B<libxml2>
  </Plugin>
 
 In the B<Plugin> block, there may be one or more B<URL> blocks, each defining a
-URL to be fetched via HTTP (using libcurl). Within each B<URL> block there are
+URL to be fetched using libcurl. Within each B<URL> block there are
 options which specify the connection parameters, for example authentication
 information, and one or more B<XPath> blocks.
 
@@ -1568,8 +1752,8 @@ debugging support.
 
 Sets the file to write log messages to. The special strings B<stdout> and
 B<stderr> can be used to write to the standard output and standard error
-channels, respectively. This, of course, only makes much sense when collectd is
-running in foreground- or non-daemon-mode.
+channels, respectively. This, of course, only makes much sense when I<collectd>
+is running in foreground- or non-daemon-mode.
 
 =item B<Timestamp> B<true>|B<false>
 
@@ -1586,6 +1770,33 @@ B<Note>: There is no need to notify the daemon after moving or removing the
 log file (e.E<nbsp>g. when rotating the logs). The plugin reopens the file
 for each line it writes.
 
+=head2 Plugin C<lpar>
+
+The I<LPAR plugin> reads CPU statistics of I<Logical Partitions>, a
+virtualization technique for IBM POWER processors. It takes into account CPU
+time stolen from or donated to a partition, in addition to the usual user,
+system, I/O statistics.
+
+The following configuration options are available:
+
+=over 4
+
+=item B<CpuPoolStats> B<false>|B<true>
+
+When enabled, statistics about the processor pool are read, too. The partition
+needs to have pool authority in order to be able to acquire this information.
+Defaults to false.
+
+=item B<ReportBySerial> B<false>|B<true>
+
+If enabled, the serial of the physical machine the partition is currently
+running on is reported as I<hostname> and the logical hostname of the machine
+is reported in the I<plugin instance>. Otherwise, the logical hostname will be
+used (just like other plugins) and the I<plugin instance> will be empty.
+Defaults to false.
+
+=back
+
 =head2 Plugin C<mbmon>
 
 The C<mbmon plugin> uses mbmon to retrieve temperature, voltage, etc.
@@ -1862,8 +2073,10 @@ Hostname of the database server. Defaults to B<localhost>.
 =item B<User> I<Username>
 
 Username to use when connecting to the database. The user does not have to be
-granted any privileges (which is synonym to granting the C<USAGE> privilege).
-Any existing MySQL user will do.
+granted any privileges (which is synonym to granting the C<USAGE> privilege),
+unless you want to collectd replication statistics (see B<MasterStats> and
+B<SlaveStats> below). In this case, the user needs the C<REPLICATION CLIENT>
+(or C<SUPER>) privileges. Else, any existing MySQL user will do.
 
 =item B<Password> I<Password>
 
@@ -1895,7 +2108,9 @@ C<mysql_real_connect> function for details.
 
 =item B<SlaveStats> I<true|false>
 
-Enable the collection of master / slave statistics in a replication setup.
+Enable the collection of master / slave statistics in a replication setup. In
+order to be able to get access to these statistics, the user needs special
+privileges. See the B<User> documentation above.
 
 =item B<SlaveNotifications> I<true|false>
 
@@ -2449,10 +2664,18 @@ The default IPv6 multicast group is C<ff18::efc0:4a42>. The default IPv4
 multicast group is C<239.192.74.66>. The default I<UDP> port is B<25826>.
 
 Both, B<Server> and B<Listen> can be used as single option or as block. When
-used as block, given options are valid for this socket only. For example:
+used as block, given options are valid for this socket only. The following
+example will export the metrics twice: Once to an "internal" server (without
+encryption and signing) and one to an external server (with cryptographic
+signature):
 
  <Plugin "network">
+   # Export to an internal server
+   # (demonstrates usage without additional options)
    Server "collectd.internal.tld"
+   
+   # Export to an external server
+   # (demonstrates usage with signature options)
    <Server "collectd.external.tld">
      SecurityLevel "sign"
      Username "myhostname"
@@ -2581,7 +2804,18 @@ operating systems.
 =item B<MaxPacketSize> I<1024-65535>
 
 Set the maximum size for datagrams received over the network. Packets larger
-than this will be truncated.
+than this will be truncated. Defaults to 1452E<nbsp>bytes, which is the maximum
+payload size that can be transmitted in one Ethernet frame using IPv6E<nbsp>/
+UDP.
+
+On the server side, this limit should be set to the largest value used on
+I<any> client. Likewise, the value on the client must not be larger than the
+value on the server, or data will be lost.
+
+B<Compatibility:> Versions prior to I<versionE<nbsp>4.8> used a fixed sized
+buffer of 1024E<nbsp>bytes. Versions I<4.8>, I<4.9> and I<4.10> used a default
+value of 1024E<nbsp>bytes to avoid problems when sending data to an older
+server.
 
 =item B<Forward> I<true|false>
 
@@ -2653,7 +2887,8 @@ and are checked by default depends on the distribution you use.
 This plugin sends a desktop notification to a notification daemon, as defined
 in the Desktop Notification Specification. To actually display the
 notifications, B<notification-daemon> is required and B<collectd> has to be
-able to access the X server.
+able to access the X server (i.E<nbsp>e., the C<DISPLAY> and C<XAUTHORITY>
+environment variables have to be set correctly) and the D-Bus message bus.
 
 The Desktop Notification Specification can be found at
 L<http://www.galago-project.org/specs/notification/>.
@@ -3225,11 +3460,6 @@ allowed as long as a single non-empty command has been specified only.
 
 The returned lines will be handled separately one after another.
 
-=item B<Query> I<sql query statement>
-
-This is a deprecated synonym for B<Statement>. It will be removed in version 5
-of collectd.
-
 =item B<Param> I<hostname>|I<database>|I<username>|I<interval>
 
 Specify the parameters which should be passed to the SQL query. The parameters
@@ -3305,21 +3535,6 @@ This option is required inside a B<Result> block and may be specified multiple
 times. If multiple B<ValuesFrom> options are specified, the columns are read
 in the given order.
 
-=item B<Column> I<type> [I<type instance>]
-
-This is a deprecated alternative to a B<Result> block. It will be removed in
-version 5 of collectd. It is equivalent to the following B<Result> block:
-
-  <Result>
-    Type I<type>
-    InstancePrefix I<type instance>
-    ValuesFrom I<name of the x. column>
-  </Result>
-
-The order of the B<Column> options defines which columns of the query result
-should be used. The first option specifies the data found in the first column,
-the second option that of the second column, and so on.
-
 =item B<MinVersion> I<version>
 
 =item B<MaxVersion> I<version>
@@ -3334,13 +3549,6 @@ The I<version> has to be specified as the concatenation of the major, minor
 and patch-level versions, each represented as two-decimal-digit numbers. For
 example, version 8.2.3 will become 80203.
 
-=item B<MinPGVersion> I<version>
-
-=item B<MaxPGVersion> I<version>
-
-These are deprecated synonyms for B<MinVersion> and B<MaxVersion>
-respectively. They will be removed in version 5 of collectd.
-
 =back
 
 The following predefined queries are available (the definitions can be found
@@ -3753,43 +3961,46 @@ Defaults to B<false>.
 
 =head2 Plugin C<redis>
 
-The C<redis> plugin connect to a list of redis servers and gather
-information about the server state. The C<redis> plugin support multiserver
-configuration, each server configuration block is called node and identify
-one redis instance (host and port).  Here is a configuration example code:
+The I<Redis plugin> connects to one or more Redis servers and gathers
+information about each server's state. For each server there is a I<Node> block
+which configures the connection parameters for this node.
 
   <Plugin redis>
-    <Node example>
+    <Node "example">
         Host "localhost"
         Port "6379"
         Timeout 2000
     </Node>
   </Plugin>
 
+The information shown in the synopsis above is the I<default configuration>
+which is used by the plugin if no configuration is present.
+
 =over 4
 
 =item B<Node> I<Nodename>
 
-The B<Node> block identify a new redis node, that is a new redis instance
-running in an specified host and port, the name for node is a canonical
-identifier which is used as plugin instance, it's limited to 64 characters
-length.
+The B<Node> block identifies a new Redis node, that is a new Redis instance
+running in an specified host and port. The name for node is a canonical
+identifier which is used as I<plugin instance>. It is limited to
+64E<nbsp>characters in length.
 
 =item B<Host> I<Hostname>
 
-The B<Host> option is the hostname or IP address (setting as string) where
-redis instance is running on.
+The B<Host> option is the hostname or IP-address where the Redis instance is
+running on.
 
 =item B<Port> I<Port>
 
-The B<Port> option is the TCP port where redis instance in IP address or
-hostname setted in B<Host> option is running.
+The B<Port> option is the TCP port on which the Redis instance accepts
+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<Timeout> I<Timeout in miliseconds>
 
-The B<Timeout> option set the socket timeout for node response. Since the
-redis read function is blocking, you may keep this value as low as possible.
-Keep in mind that the sum of all Timeout values for all Nodes might be lower
+The B<Timeout> option set the socket timeout for node response. Since the Redis
+read function is blocking, you should keep this value as low as possible. Keep
+in mind that the sum of all B<Timeout> values for all B<Nodes> should be lower
 than B<Interval> defined globally.
 
 =back
@@ -3957,7 +4168,7 @@ because all values were added to the internal cache at roughly the same time.
 
 =head2 Plugin C<sensors>
 
-The C<sensors plugin> uses B<lm_sensors> to retrieve sensor-values. This means
+The I<Sensors plugin> uses B<lm_sensors> to retrieve sensor-values. This means
 that all the needed modules have to be loaded and lm_sensors has to be
 configured (most likely by editing F</etc/sensors.conf>. Read
 L<sensors.conf(5)> for details.
@@ -3992,6 +4203,25 @@ Since the configuration of the C<snmp plugin> is a little more complicated than
 other plugins, its documentation has been moved to an own manpage,
 L<collectd-snmp(5)>. Please see there for details.
 
+=head2 Plugin C<swap>
+
+The I<Swap plugin> collects information about used and available swap space. On
+I<Solaris>, the following options are available:
+
+=over 4
+
+=item B<ReportByDevice> B<false>|B<true>
+
+Configures how to report physical swap devices. If set to B<false> is used (the
+default), the summary over all swap devices is reported only, i.e. the globally
+used and available space over all devices. If B<true> is configured, the used
+and available space of each device will be reported separately.
+
+This option is only available if the I<Swap plugin> can use the L<swapctl(2)>
+mechanism under I<Solaris>.
+
+=back
+
 =head2 Plugin C<syslog>
 
 =over 4
@@ -4190,25 +4420,37 @@ Use the last number found.
 
 =item B<CounterSet>
 
-The matched number is a counter. Simply sets the internal counter to this
-value.
+=item B<DeriveSet>
+
+=item B<AbsoluteSet>
+
+The matched number is a counter. Simply I<sets> the internal counter to this
+value. Variants exist for C<COUNTER>, C<DERIVE>, and C<ABSOLUTE> data sources.
 
 =item B<CounterAdd>
 
-Add the matched value to the internal counter.
+=item B<DeriveAdd>
+
+Add the matched value to the internal counter. In case of B<DeriveAdd>, the
+matched number may be negative, which will effectively subtract from the
+internal counter.
 
 =item B<CounterInc>
 
-Increase the internal counter by one. This B<DSType> is the only one that does
-not use the matched subexpression, but simply counts the number of matched
+=item B<DeriveInc>
+
+Increase the internal counter by one. These B<DSType> are the only ones that do
+not use the matched subexpression, but simply count the number of matched
 lines. Thus, you may use a regular expression without submatch in this case.
 
 =back
 
 As you'd expect the B<Gauge*> types interpret the submatch as a floating point
-number, using L<strtod(3)>. The B<CounterSet> and B<CounterAdd> interpret the
-submatch as an integer using L<strtoll(3)>. B<CounterInc> does not use the
-submatch at all and it may be omitted in this case.
+number, using L<strtod(3)>. The B<Counter*> and B<AbsoluteSet> types interpret
+the submatch as an unsigned integer using L<strtoull(3)>. The B<Derive*> types
+interpret the submatch as a signed integer using L<strtoll(3)>. B<CounterInc>
+and B<DeriveInc> do not use the submatch at all and it may be omitted in this
+case.
 
 =item B<Type> I<Type>
 
@@ -4329,7 +4571,7 @@ port in numeric form.
 
 =item B<ForceUseProcfs> I<true>|I<false>
 
-By default, the C<thermal> plugin tries to read the statistics from the Linux
+By default, the I<Thermal plugin> tries to read the statistics from the Linux
 C<sysfs> interface. If that is not available, the plugin falls back to the
 C<procfs> interface. By setting this option to I<true>, you can force the
 plugin to use the latter. This option defaults to I<false>.
@@ -4349,9 +4591,18 @@ selection is configured at all, B<all> devices are selected.
 
 =back
 
+=head2 Plugin C<threshold>
+
+The I<Threshold plugin> checks values collected or received by I<collectd>
+against a configurable I<threshold> and issues I<notifications> if values are
+out of bounds.
+
+Documentation for this plugin is available in the L<collectd-threshold(5)>
+manual page.
+
 =head2 Plugin C<tokyotyrant>
 
-The C<tokyotyrant plugin> connects to a TokyoTyrant server and collects a
+The I<TokyoTyrant plugin> connects to a TokyoTyrant server and collects a
 couple metrics: number of records, and database size on disk.
 
 =over 4
@@ -4388,6 +4639,13 @@ Change the file permissions of the UNIX-socket after it has been created. The
 permissions must be given as a numeric, octal value as you would pass to
 L<chmod(1)>. Defaults to B<0770>.
 
+=item B<DeleteSocket> B<false>|B<true>
+
+If set to B<true>, delete the socket file before calling L<bind(2)>, if a file
+with the given name already exists. If I<collectd> crashes a socket file may be
+left over, preventing the daemon from opening a new socket when restarted.
+Since this is potentially dangerous, this defaults to B<false>.
+
 =back
 
 =head2 Plugin C<uuid>
@@ -4653,13 +4911,6 @@ information.
          WarningMin 100000000
        </Type>
      </Plugin>
-
-     <Type "load">
-     	DataSource "midterm"
-     	FailureMax 4
-     	Hits 3
-     	Hysteresis 3
-     </Type>
    </Host>
  </Threshold>
 
@@ -4732,26 +4983,33 @@ percentage value, relative to the other data sources. This is helpful for
 example for the "df" type, where you may want to issue a warning when less than
 5E<nbsp>% of the total space is available. Defaults to B<false>.
 
-=item B<Hits> I<Value>
+=item B<Hits> I<Number>
+
+Delay creating the notification until the threshold has been passed I<Number>
+times. When a notification has been generated, or when a subsequent value is
+inside the threshold, the counter is reset. If, for example, a value is
+collected once every 10E<nbsp>seconds and B<Hits> is set to 3, a notification
+will be dispatched at most once every 30E<nbsp>seconds.
+
+This is useful when short bursts are not a problem. If, for example, 100% CPU
+usage for up to a minute is normal (and data is collected every
+10E<nbsp>seconds), you could set B<Hits> to B<6> to account for this.
 
-Sets the number of occurrences which the threshold must be arised before to
-dispatch any notification or, in other words, the number of B<Interval>s
-than the threshold must be match before dispatch any notification.
+=item B<Hysteresis> I<Number>
 
-=item B<Hysteresis> I<Value>
+When set to non-zero, a hysteresis value is applied when checking minimum and
+maximum bounds. This is useful for values that increase slowly and fluctuate a
+bit while doing so. When these values come close to the threshold, they may
+"flap", i.e. switch between failure / warning case and okay case repeatedly.
 
-Sets the hysteresis value for threshold. The hysteresis is a method to
-prevent flapping between states, until a new received value for
-a previously matched threshold down below the threshold condition
-(B<WarningMax>, B<FailureMin> or everthing else) minus the hysteresis value,
-the failure (respectively warning) state will be keep.
+If, for example, the threshold is configures as
 
-=item B<Interesting> B<true>|B<false>
+  WarningMax 100.0
+  Hysteresis 1.0
 
-If set to B<true> (the default), the threshold must be treated as
-interesting and, when a number of B<Timeout> values will lost, then
-a missing notification will be dispatched. On the other hand, if set to
-B<false>, the missing notification will never dispatched for this threshold.
+then a I<Warning> notification is created when the value exceeds I<101> and the
+corresponding I<Okay> notification is only created once the value falls below
+I<99>, thus avoiding the "flapping".
 
 =back