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
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. By default, this is disabled.
+
+This is useful (or possibly even required), e.E<nbsp>g., when loading a plugin
+that embeds some scripting language into the daemon (e.E<nbsp>g. the C<perl>
+or C<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.E<nbsp>g.,
+L<collectd-perl(5)> or L<collectd-python(5)>) for details.
+
+=back
+
=item B<Include> I<Path>
If I<Path> points to a file, includes that file. If I<Path> points to a
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
+I<Iterations> iterations. By default, I<collectd> considers a value list
+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.
+
=item B<ReadThreads> I<Num>
Number of threads to start for reading plugins. The default value is B<5>, but
=back
+=head2 Plugin C<curl_xml>
+
+The B<curl_xml plugin> uses B<libcurl> (L<http://curl.haxx.se/>) and B<libxml2>
+(L<http://xmlsoft.org/>) to retrieve XML data via cURL.
+
+ <Plugin "curl_xml">
+ <URL "http://localhost/stats.xml">
+ Host "my_host"
+ Instance "some_instance"
+ User "collectd"
+ Password "thaiNg0I"
+ VerifyPeer true
+ VerifyHost true
+ CACert "/path/to/ca.crt"
+
+ <XPath "table[@id=\"magic_level\"]/tr">
+ Type "magic_level"
+ #InstancePrefix "prefix-"
+ InstanceFrom "td[1]"
+ ValuesFrom "td[2]/span[@class=\"level\"]"
+ </XPath>
+ </URL>
+ </Plugin>
+
+In the B<Plugin> block, there may be one or more B<URL> blocks, each defining a
+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.
+
+Each B<XPath> block specifies how to get one type of information. The
+string argument must be a valid XPath expression which returns a list
+of "base elements". One value is dispatched for each "base element". The
+I<type instance> and values are looked up using further I<XPath> expressions
+that should be relative to the base element.
+
+Within the B<URL> block the following options are accepted:
+
+=over 4
+
+=item B<Host> I<Name>
+
+Use I<Name> as the host name when submitting values. Defaults to the global
+host name setting.
+
+=item B<Instance> I<Instance>
+
+Use I<Instance> as the plugin instance when submitting values. Defaults to an
+empty string (no plugin instance).
+
+=item B<User> I<User>
+=item B<Password> I<Password>
+=item B<VerifyPeer> B<true>|B<false>
+=item B<VerifyHost> B<true>|B<false>
+=item B<CACert> I<CA Cert File>
+
+These options behave exactly equivalent to the appropriate options of the
+I<cURL> and I<cURL-JSON> plugins. Please see there for a detailed description.
+
+=item E<lt>B<XPath> I<XPath-expression>E<gt>
+
+Within each B<URL> block, there must be one or more B<XPath> blocks. Each
+B<XPath> block specifies how to get one type of information. The string
+argument must be a valid XPath expression which returns a list of "base
+elements". One value is dispatched for each "base element".
+
+Within the B<XPath> block the following options are accepted:
+
+=over 4
+
+=item B<Type> I<Type>
+
+Specifies the I<Type> used for submitting patches. This determines the number
+of values that are required / expected and whether the strings are parsed as
+signed or unsigned integer or as double values. See L<types.db(5)> for details.
+This option is required.
+
+=item B<InstancePrefix> I<InstancePrefix>
+
+Prefix the I<type instance> with I<InstancePrefix>. The values are simply
+concatenated together without any separator.
+This option is optional.
+
+=item B<InstanceFrom> I<InstanceFrom>
+
+Specifies a XPath expression to use for determining the I<type instance>. The
+XPath expression must return exactly one element. The element's value is then
+used as I<type instance>, possibly prefixed with I<InstancePrefix> (see above).
+
+This value is required. As a special exception, if the "base XPath expression"
+(the argument to the B<XPath> block) returns exactly one argument, then this
+option may be omitted.
+
+=item B<ValuesFrom> I<ValuesFrom> [I<ValuesFrom> ...]
+
+Specifies one or more XPath expression to use for reading the values. The
+number of XPath expressions must match the number of data sources in the
+I<type> specified with B<Type> (see above). Each XPath expression must return
+exactly one element. The element's value is then parsed as a number and used as
+value for the appropriate value in the value list dispatched to the daemon.
+
+=back
+
+=back
+
=head2 Plugin C<dbi>
This plugin uses the B<dbi> library (L<http://libdbi.sourceforge.net/>) to
Controls whether or not to recurse into subdirectories. Enabled by default.
+=item B<IncludeHidden> I<true>|I<false>
+
+Controls whether or not to include "hidden" files and directories in the count.
+"Hidden" files and directories are those, whose name begins with a dot.
+Defaults to I<false>, i.e. by default hidden files and directories are ignored.
+
=back
=head2 Plugin C<GenericJMX>
Prefix all lines printed by the current time. Defaults to B<true>.
+=item B<PrintSeverity> B<true>|B<false>
+
+When enabled, all lines are prefixed by the severity of the log message, for
+example "warning". Defaults to B<false>.
+
=back
B<Note>: There is no need to notify the daemon after moving or removing the
=back
+=head2 Plugin C<modbus>
+
+The B<modbus plugin> connects to a Modbus "slave" via Modbus/TCP and reads
+register values. It supports reading single registers (unsigned 16E<nbsp>bit
+values), large integer values (unsigned 32E<nbsp>bit values) and floating point
+values (two registers interpreted as IEEE floats in big endian notation).
+
+Synopsis:
+
+ <Data "voltage-input-1">
+ RegisterBase 0
+ RegisterType float
+ Type voltage
+ Instance "input-1"
+ </Data>
+
+ <Data "voltage-input-2">
+ RegisterBase 2
+ RegisterType float
+ Type voltage
+ Instance "input-2"
+ </Data>
+
+ <Host "modbus.example.com">
+ Address "192.168.0.42"
+ Port "502"
+ Interval 60
+
+ <Slave 1>
+ Instance "power-supply"
+ Collect "voltage-input-1"
+ Collect "voltage-input-2"
+ </Slave>
+ </Host>
+
+=over 4
+
+=item E<lt>B<Data> I<Name>E<gt> blocks
+
+Data blocks define a mapping between register numbers and the "types" used by
+I<collectd>.
+
+Within E<lt>DataE<nbsp>/E<gt> blocks, the following options are allowed:
+
+=over 4
+
+=item B<RegisterBase> I<Number>
+
+Configures the base register to read from the device. If the option
+B<RegisterType> has been set to B<Uint32> or B<Float>, this and the next
+register will be read (the register number is increased by one).
+
+=item B<RegisterType> B<Uint16>|B<Uint32>|B<Float>
+
+Specifies what kind of data is returned by the device. If the type is B<Uint32>
+or B<Float>, two 16E<nbsp>bit registers will be read and the data is combined
+into one value. Defaults to B<Uint16>.
+
+=item B<Type> I<Type>
+
+Specifies the "type" (data set) to use when dispatching the value to
+I<collectd>. Currently, only data sets with exactly one data source are
+supported.
+
+=item B<Instance> I<Instance>
+
+Sets the type instance to use when dispatching the value to I<collectd>. If
+unset, an empty string (no type instance) is used.
+
+=back
+
+=item E<lt>B<Host> I<Name>E<gt> blocks
+
+Host blocks are used to specify to which hosts to connect and what data to read
+from their "slaves". The string argument I<Name> is used as hostname when
+dispatching the values to I<collectd>.
+
+Within E<lt>HostE<nbsp>/E<gt> blocks, the following options are allowed:
+
+=over 4
+
+=item B<Address> I<Hostname>
+
+Specifies the node name (the actual network address) used to connect to the
+host. This may be an IP address or a hostname. Please note that the used
+I<libmodbus> library only supports IPv4 at the moment.
+
+=item B<Port> I<Service>
+
+Specifies the port used to connect to the host. The port can either be given as
+a number or as a service name. Please note that the I<Service> argument must be
+a string, even if ports are given in their numerical form. Defaults to "502".
+
+=item B<Interval> I<Interval>
+
+Sets the interval (in seconds) in which the values will be collected from this
+host. By default the global B<Interval> setting will be used.
+
+=item E<lt>B<Slave> I<ID>E<gt>
+
+Over each TCP connection, multiple Modbus devices may be reached. The slave ID
+is used to specify which device should be addressed. For each device you want
+to query, one B<Slave> block must be given.
+
+Within E<lt>SlaveE<nbsp>/E<gt> blocks, the following options are allowed:
+
+=over 4
+
+=item B<Instance> I<Instance>
+
+Specify the plugin instance to use when dispatching the values to I<collectd>.
+By default "slave_I<ID>" is used.
+
+=item B<Collect> I<DataName>
+
+Specifies which data to retrieve from the device. I<DataName> must be the same
+string as the I<Name> argument passed to a B<Data> block. You can specify this
+option multiple times to collect more than one value from a slave. At least one
+B<Collect> option is mandatory.
+
+=back
+
+=back
+
+=back
+
=head2 Plugin C<mysql>
The C<mysql plugin> requires B<mysqlclient> to be installed. It connects to
=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>
=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>
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"
This feature is only available if the I<network> plugin was linked with
I<libgcrypt>.
+=item B<Interface> I<Interface name>
+
+Set the outgoing interface for IP packets. This applies at least
+to IPv6 packets and if possible to IPv4. If this option is not applicable,
+undefined or a non-existent interface name is specified, the default
+behavior is to let the kernel choose the appropriate interface. Be warned
+that the manual selection of an interface for unicast traffic is only
+necessary in rare cases.
+
=back
=item B<E<lt>Listen> I<Host> [I<Port>]B<E<gt>>
using L<stat(2)>. If the file has been changed, the contents is re-read. While
the file is being read, it is locked using L<fcntl(2)>.
+=item B<Interface> I<Interface name>
+
+Set the incoming interface for IP packets explicitly. This applies at least
+to IPv6 packets and if possible to IPv4. If this option is not applicable,
+undefined or a non-existent interface name is specified, the default
+behavior is, to let the kernel choose the appropriate interface. Thus incoming
+traffic gets only accepted, if it arrives on the given interface.
+
=back
=item B<TimeToLive> I<1-255>
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/>.
when reading multiple status files. Enabling this option is recommended, but to
maintain backwards compatibility this option is disabled by default.
-=item B<Compression> B<true>|B<false>
+=item B<CollectCompression> B<true>|B<false>
Sets whether or not statistics about the compression used by OpenVPN should be
collected. This information is only available in I<single> mode. Enabled by
default.
+=item B<CollectIndividualUsers> B<true>|B<false>
+
+Sets whether or not traffic information is collected for each connected client
+individually. If set to false, currently no traffic data is collected at all
+because aggregating this data in a save manner is tricky. Defaults to B<true>.
+
+=item B<CollectUserCount> B<true>|B<false>
+
+When enabled, the number of currently connected clients or users is collected.
+This is especially interesting when B<CollectIndividualUsers> is disabled, but
+can be configured independently from that option. Defaults to B<false>.
+
=back
=head2 Plugin C<oracle>
This plugin embeds a Perl-interpreter into collectd and provides an interface
to collectd's plugin system. See L<collectd-perl(5)> for its documentation.
+=head2 Plugin C<pinba>
+
+The I<Pinba plugin> receives profiling information from I<Pinba>, an extension
+for the I<PHP> interpreter. At the end of executing a script, i.e. after a
+PHP-based webpage has been delivered, the extension will send a UDP packet
+containing timing information, peak memory usage and so on. The plugin will
+wait for such packets, parse them and account the provided information, which
+is then dispatched to the daemon once per interval.
+
+Synopsis:
+
+ <Plugin pinba>
+ Address "::0"
+ Port "30002"
+ # Overall statistics for the website.
+ <View "www-total">
+ Server "www.example.com"
+ </View>
+ # Statistics for www-a only
+ <View "www-a">
+ Host "www-a.example.com"
+ Server "www.example.com"
+ </View>
+ # Statistics for www-b only
+ <View "www-b">
+ Host "www-b.example.com"
+ Server "www.example.com"
+ </View>
+ </Plugin>
+
+The plugin provides the following configuration options:
+
+=over 4
+
+=item B<Address> I<Node>
+
+Configures the address used to open a listening socket. By default, plugin will
+bind to the I<any> address C<::0>.
+
+=item B<Port> I<Service>
+
+Configures the port (service) to bind to. By default the default Pinba port
+"30002" will be used. The option accepts service names in addition to port
+numbers and thus requires a I<string> argument.
+
+=item E<lt>B<View> I<Name>E<gt> block
+
+The packets sent by the Pinba extension include the hostname of the server, the
+server name (the name of the virtual host) and the script that was executed.
+Using B<View> blocks it is possible to separate the data into multiple groups
+to get more meaningful statistics. Each packet is added to all matching groups,
+so that a packet may be accounted for more than once.
+
+=over 4
+
+=item B<Host> I<Host>
+
+Matches the hostname of the system the webserver / script is running on. This
+will contain the result of the L<gethostname(2)> system call. If not
+configured, all hostnames will be accepted.
+
+=item B<Server> I<Server>
+
+Matches the name of the I<virtual host>, i.e. the contents of the
+C<$_SERVER["SERVER_NAME"]> variable when within PHP. If not configured, all
+server names will be accepted.
+
+=item B<Script> I<Script>
+
+Matches the name of the I<script name>, i.e. the contents of the
+C<$_SERVER["SCRIPT_NAME"]> variable when within PHP. If not configured, all
+script names will be accepted.
+
+=back
+
+=back
+
=head2 Plugin C<ping>
The I<Ping> plugin starts a new thread which sends ICMP "ping" packets to the
=item B<MaxMissed> I<Packets>
-Trigger a DNS resolv after the host has not replied to I<Packets> packets. This
+Trigger a DNS resolve after the host has not replied to I<Packets> packets. This
enables the use of dynamic DNS services (like dyndns.org) with the ping plugin.
Default: B<-1> (disabled)
</Database>
<Database bar>
+ Interval 300
Service "service_name"
Query backend # predefined
Query rt36_tickets
=item I<interval>
-The interval collectd is using (as specified by the B<Interval> option).
+The interval with which this database is queried (as specified by the database
+specific or global B<Interval> options).
=back
=over 4
+=item B<Interval> I<seconds>
+
+Specify the interval with which the database should be queried. The default is
+to use the global B<Interval> setting.
+
=item B<Host> I<hostname>
Specify the hostname or IP of the PostgreSQL server to connect to. If the
User "collectd"
Password "secr3t"
CollectInterface true
+ CollectCPULoad true
+ CollectMemory true
</Router>
<Router>
Host "router1.example.com"
Password "5ecret"
CollectInterface true
CollectRegistrationTable true
+ CollectDF true
+ CollectDisk true
</Router>
</Plugin>
When set to B<true>, information about wireless LAN connections will be
collected. Defaults to B<false>.
+=item B<CollectCPULoad> B<true>|B<false>
+
+When set to B<true>, information about the CPU usage will be collected. The
+number is a dimensionless value where zero indicates no CPU usage at all.
+Defaults to B<false>.
+
+=item B<CollectMemory> B<true>|B<false>
+
+When enabled, the amount of used and free memory will be collected. How used
+memory is calculated is unknown, for example whether or not caches are counted
+as used space.
+Defaults to B<false>.
+
+=item B<CollectDF> B<true>|B<false>
+
+When enabled, the amount of used and free disk space will be collected.
+Defaults to B<false>.
+
+=item B<CollectDisk> B<true>|B<false>
+
+When enabled, the number of sectors written and bad blocks will be collected.
+Defaults to B<false>.
+
=back
=head2 Plugin C<rrdcached>
</Match>
<Match>
Regex "\\<R=local_user\\>"
+ ExcludeRegex "\\<R=local_user\\>.*mail_spool defer"
DSType "CounterInc"
Type "counter"
Instance "local_user"
Regex "SPAM \\(Score: (-?[0-9]+\\.[0-9]+)\\)"
+=item B<ExcludeRegex> I<regex>
+
+Sets an optional regular expression to use for excluding lines from the match.
+An example which excludes all connections from localhost from the match:
+
+ ExcludeRegex "127\\.0\\.0\\.1"
+
=item B<DSType> I<Type>
Sets how the values are cumulated. I<Type> is one of:
=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>
Defaults to B<Command>.
+=item B<StoreRates> B<true|false>
+
+If set to B<true>, convert counter values to rates. If set to B<false> (the
+default) counter values are stored as is, i.E<nbsp>e. as an increasing integer
+number.
+
=back
=head1 THRESHOLD CONFIGURATION
Also, all values that match a threshold are considered to be relevant or
"interesting". As a consequence collectd will issue a notification if they are
-not received for twice the last timeout of the values. If, for example, some
-hosts sends it's CPU statistics to the server every 60 seconds, a notification
-will be dispatched after about 120 seconds. It may take a little longer because
-the timeout is checked only once each B<Interval> on the server.
+not received for B<Timeout> iterations. The B<Timeout> configuration option is
+explained in section L<"GLOBAL OPTIONS">. If, for example, B<Timeout> is set to
+"2" (the default) and some hosts sends it's CPU statistics to the server every
+60 seconds, a notification will be dispatched after about 120 seconds. It may
+take a little longer because the timeout is checked only once each B<Interval>
+on the server.
When a value comes within range again or is received after it was missing, an
"OKAY-notification" is dispatched.
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<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.
+
+=item B<Hysteresis> I<Number>
+
+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.
+
+If, for example, the threshold is configures as
+
+ WarningMax 100.0
+ Hysteresis 1.0
+
+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
=head1 FILTER CONFIGURATION
the identifier of a value. If multiple regular expressions are given, B<all>
regexen must match for a value to match.
+=item B<Invert> B<false>|B<true>
+
+When set to B<true>, the result of the match is inverted, i.e. all value lists
+where all regular expressions apply are not matched, all other value lists are
+matched. Defaults to B<false>.
+
=back
Example: