+=item B<SMTPPort> I<Port>
+
+TCP port to connect to.
+
+Default: C<25>
+
+=item B<SMTPUser> I<Username>
+
+Username for ASMTP authentication. Optional.
+
+=item B<SMTPPassword> I<Password>
+
+Password for ASMTP authentication. Optional.
+
+=item B<Subject> I<Subject>
+
+Subject-template to use when sending emails. There must be exactly two
+string-placeholders in the subject, given in the standard I<printf(3)> syntax,
+i.E<nbsp>e. C<%s>. The first will be replaced with the severity, the second
+with the hostname.
+
+Default: C<Collectd notify: %s@%s>
+
+=back
+
+=head2 Plugin C<ntpd>
+
+=over 4
+
+=item B<Host> I<Hostname>
+
+Hostname of the host running B<ntpd>. Defaults to B<localhost>.
+
+=item B<Port> I<Port>
+
+UDP-Port to connect to. Defaults to B<123>.
+
+=item B<ReverseLookups> B<true>|B<false>
+
+Sets wether or not to perform reverse lookups on peers. Since the name or
+IP-address may be used in a filename it is recommended to disable reverse
+lookups. The default is to do reverse lookups to preserve backwards
+compatibility, though.
+
+=back
+
+=head2 Plugin C<nut>
+
+=over 4
+
+=item B<UPS> I<upsname>B<@>I<hostname>[B<:>I<port>]
+
+Add a UPS to collect data from. The format is identical to the one accepted by
+L<upsc(8)>.
+
+=back
+
+=head2 Plugin C<onewire>
+
+B<EXPERIMENTAL!> See notes below.
+
+The C<onewire> plugin uses the B<owcapi> library from the B<owfs> project
+L<http://owfs.org/> to read sensors connected via the onewire bus.
+
+Currently only temperature sensors (sensors with the family code C<10>,
+e.E<nbsp>g. DS1820, DS18S20, DS1920) can be read. If you have other sensors you
+would like to have included, please send a sort request to the mailing list.
+
+Hubs (the DS2409 chips) are working, but read the note, why this plugin is
+experimental, below.
+
+=over 4
+
+=item B<Device> I<Device>
+
+Sets the device to read the values from. This can either be a "real" hardware
+device, such as a serial port or an USB port, or the address of the
+L<owserver(1)> socket, usually B<localhost:4304>.
+
+Though the documentation claims to automatically recognize the given address
+format, with versionE<nbsp>2.7p4 we had to specify the type explicitly. So
+with that version, the following configuration worked for us:
+
+ <Plugin onewire>
+ Device "-s localhost:4304"
+ </Plugin>
+
+This directive is B<required> and does not have a default value.
+
+=item B<Sensor> I<Sensor>
+
+Selects sensors to collect or to ignore, depending on B<IgnoreSelected>, see
+below. Sensors are specified without the family byte at the beginning, to you'd
+use C<F10FCA000800>, and B<not> include the leading C<10.> family byte and
+point.
+
+=item B<IgnoreSelected> I<true>|I<false>
+
+If no configuration if given, the B<onewire> plugin will collect data from all
+sensors found. This may not be practical, especially if sensors are added and
+removed regularly. Sometimes, however, it's easier/preferred to collect only
+specific sensors or all sensors I<except> a few specified ones. This option
+enables you to do that: By setting B<IgnoreSelected> to I<true> the effect of
+B<Sensor> is inverted: All selected interfaces are ignored and all other
+interfaces are collected.
+
+=back
+
+B<EXPERIMENTAL!> The C<onewire> plugin is experimental, because it doesn't yet
+work with big setups. It works with one sensor being attached to one
+controller, but as soon as you throw in a couple more senors and maybe a hub
+or two, reading all values will take more than ten seconds (the default
+interval). We will probably add some separate thread for reading the sensors
+and some cache or something like that, but it's not done yet. We will try to
+maintain backwards compatibility in the future, but we can't promise. So in
+short: If it works for you: Great! But keep in mind that the config I<might>
+change, though this is unlikely. Oh, and if you want to help improving this
+plugin, just send a short notice to the mailing list. ThanksE<nbsp>:)
+
+=head2 Plugin C<openvpn>
+
+The OpenVPN plugin reads a status file maintained by OpenVPN and gathers
+traffic statistics about connected clients.
+
+To set up OpenVPN to write to the status file periodically, use the
+B<--status> option of OpenVPN. Since OpenVPN can write two different formats,
+you need to set the required format, too. This is done by setting
+B<--status-version> to B<2>.
+
+So, in a nutshell you need:
+
+ openvpn $OTHER_OPTIONS \
+ --status "/var/run/openvpn-status" 10 \
+ --status-version 2
+
+Available options:
+
+=over 4
+
+=item B<StatusFile> I<File>
+
+Specifies the location of the status file.
+
+=back
+
+=head2 Plugin C<oracle>
+
+The "oracle" plugin uses the Oracle® Call Interface I<(OCI)> to connect to an
+Oracle® Database and lets you execute SQL statements there. It is very similar
+to the "dbi" plugin, because it was written around the same time. See the "dbi"
+plugin's documentation above for details.
+
+ <Plugin oracle>
+ <Query "out_of_stock">
+ Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
+ <Result>
+ Type "gauge"
+ # InstancePrefix "foo"
+ InstancesFrom "category"
+ ValuesFrom "value"
+ </Result>
+ </Query>
+ <Database "product_information">
+ ConnectID "db01"
+ Username "oracle"
+ Password "secret"
+ Query "out_of_stock"
+ </Database>
+ </Plugin>
+
+=head3 B<Query> blocks
+
+The Query blocks are handled identically to the Query blocks of the "dbi"
+plugin. Please see its documentation above for details on how to specify
+queries.
+
+=head3 B<Database> blocks
+
+Database blocks define a connection to a database and which queries should be
+sent to that database. Each database needs a "name" as string argument in the
+starting tag of the block. This name will be used as "PluginInstance" in the
+values submitted to the daemon. Other than that, that name is not used.
+
+=over 4
+
+=item B<ConnectID> I<ID>
+
+Defines the "database alias" or "service name" to connect to. Usually, these
+names are defined in the file named C<$ORACLE_HOME/network/admin/tnsnames.ora>.
+
+=item B<Username> I<Username>
+
+Username used for authentication.
+
+=item B<Password> I<Password>
+
+Password used for authentication.
+
+=item B<Query> I<QueryName>
+
+Associates the query named I<QueryName> with this database connection. The
+query needs to be defined I<before> this statement, i.E<nbsp>e. all query
+blocks you want to refer to must be placed above the database block you want to
+refer to them from.
+
+=back
+
+=head2 Plugin C<perl>
+
+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<ping>
+
+=over 4
+
+=item B<Host> I<IP-address>
+
+Host to ping periodically. This option may be repeated several times to ping
+multiple hosts.
+
+=item B<TTL> I<0-255>
+
+Sets the Time-To-Live of generated ICMP packets.
+
+=back
+
+=head2 Plugin C<postgresql>
+
+The C<postgresql> plugin queries statistics from PostgreSQL databases. It
+keeps a persistent connection to all configured databases and tries to
+reconnect if the connection has been interrupted. A database is configured by
+specifying a B<Database> block as described below. The default statistics are
+collected from PostgreSQL's B<statistics collector> which thus has to be
+enabled for this plugin to work correctly. This should usually be the case by
+default. See the section "The Statistics Collector" of the B<PostgreSQL
+Documentation> for details.
+
+By specifying custom database queries using a B<Query> block as described
+below, you may collect any data that is available from some PostgreSQL
+database. This way, you are able to access statistics of external daemons
+which are available in a PostgreSQL database or use future or special
+statistics provided by PostgreSQL without the need to upgrade your collectd
+installation.
+
+The B<PostgreSQL Documentation> manual can be found at
+L<http://www.postgresql.org/docs/manuals/>.
+
+ <Plugin postgresql>
+ <Query magic>
+ Statement "SELECT magic FROM wizard WHERE host = $1;"
+ Param hostname
+ <Result>
+ Type gauge
+ InstancePrefix "magic"
+ ValuesFrom magic
+ </Result>
+ </Query>
+
+ <Query rt36_tickets>
+ Statement "SELECT COUNT(type) AS count, type \
+ FROM (SELECT CASE \
+ WHEN resolved = 'epoch' THEN 'open' \
+ ELSE 'resolved' END AS type \
+ FROM tickets) type \
+ GROUP BY type;"
+ <Result>
+ Type counter
+ InstancePrefix "rt36_tickets"
+ InstancesFrom "type"
+ ValuesFrom "count"
+ </Result>
+ </Query>
+
+ <Database foo>
+ Host "hostname"
+ Port "5432"
+ User "username"
+ Password "secret"
+ SSLMode "prefer"
+ KRBSrvName "kerberos_service_name"
+ Query magic
+ </Database>
+
+ <Database bar>
+ Service "service_name"
+ Query backend # predefined
+ Query rt36_tickets
+ </Database>
+ </Plugin>
+
+The B<Query> block defines one database query which may later be used by a
+database definition. It accepts a single mandatory argument which specifies
+the name of the query. The names of all queries have to be unique (see the
+B<MinPGVersion> and B<MaxPGVersion> options below for an exception to this
+rule). The following configuration options are available to define the query:
+
+In each B<Query> block, there is one or more B<Result> blocks. B<Result>
+blocks define how to handle the values returned from the query. They define
+which column holds which value and how to dispatch that value to the daemon.
+Multiple B<Result> blocks may be used to extract multiple values from a single
+query.
+
+=over 4
+
+=item B<Statement> I<sql query statement>
+
+Specify the I<sql query statement> which the plugin should execute. The string
+may contain the tokens B<$1>, B<$2>, etc. which are used to reference the
+first, second, etc. parameter. The value of the parameters is specified by the
+B<Param> configuration option - see below for details. To include a literal
+B<$> character followed by a number, surround it with single quotes (B<'>).
+
+Any SQL command which may return data (such as C<SELECT> or C<SHOW>) is
+allowed. Note, however, that only a single command may be used. Semicolons are
+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
+are referred to in the SQL query as B<$1>, B<$2>, etc. in the same order as
+they appear in the configuration file. The value of the parameter is
+determined depending on the value of the B<Param> option as follows:
+
+=over 4
+
+=item I<hostname>
+
+The configured hostname of the database connection. If a UNIX domain socket is
+used, the parameter expands to "localhost".
+
+=item I<database>
+
+The name of the database of the current connection.
+
+=item I<username>
+
+The username used to connect to the database.
+
+=item I<interval>
+
+The interval collectd is using (as specified by the B<Interval> option).
+
+=back
+
+Please note that parameters are only supported by PostgreSQL's protocol
+version 3 and above which was introduced in version 7.4 of PostgreSQL.
+
+=item B<Type> I<type>
+
+The I<type> name to be used when dispatching the values. The type describes
+how to handle the data and where to store it. See L<types.db(5)> for more
+details on types and their configuration. The number and type of values (as
+selected by the B<ValuesFrom> option) has to match the type of the given name.
+
+This option is required inside a B<Result> block.
+
+=item B<InstancePrefix> I<prefix>
+
+=item B<InstancesFrom> I<column0> [I<column1> ...]
+
+Specify how to create the "TypeInstance" for each data set (i.E<nbsp>e. line).
+B<InstancePrefix> defines a static prefix that will be prepended to all type
+instances. B<InstancesFrom> defines the column names whose values will be used
+to create the type instance. Multiple values will be joined together using the
+hyphen (C<->) as separation character.
+
+The plugin itself does not check whether or not all built instances are
+different. It is your responsibility to assure that each is unique.
+
+Both options are optional. If none is specified, the type instance will be
+empty.
+
+=item B<ValuesFrom> I<column0> [I<column1> ...]
+
+Names the columns whose content is used as the actual data for the data sets
+that are dispatched to the daemon. How many such columns you need is
+determined by the B<Type> setting as explained above. If you specify too many
+or not enough columns, the plugin will complain about that and no data will be
+submitted to the daemon.
+
+The actual data type, as seen by PostgreSQL, is not that important as long as
+it represents numbers. The plugin will automatically cast the values to the
+right type if it know how to do that. For that, it uses the L<strtoll(3)> and
+L<strtod(3)> functions, so anything supported by those functions is supported
+by the plugin as well.
+
+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<MinPGVersion> I<version>
+
+=item B<MaxPGVersion> I<version>
+
+Specify the minimum or maximum version of PostgreSQL that this query should be
+used with. Some statistics might only be available with certain versions of
+PostgreSQL. This allows you to specify multiple queries with the same name but
+which apply to different versions, thus allowing you to use the same
+configuration in a heterogeneous environment.
+
+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.
+
+=back
+
+The following predefined queries are available (the definitions can be found
+in the F<postgresql_default.conf> file which, by default, is available at
+C<I<prefix>/share/collectd/>):
+
+=over 4
+
+=item B<backends>
+
+This query collects the number of backends, i.E<nbsp>e. the number of
+connected clients.
+
+=item B<transactions>
+
+This query collects the numbers of committed and rolled-back transactions of
+the user tables.
+
+=item B<queries>
+
+This query collects the numbers of various table modifications (i.E<nbsp>e.
+insertions, updates, deletions) of the user tables.
+
+=item B<query_plans>
+
+This query collects the numbers of various table scans and returned tuples of
+the user tables.
+
+=item B<table_states>
+
+This query collects the numbers of live and dead rows in the user tables.
+
+=item B<disk_io>
+
+This query collects disk block access counts for user tables.
+
+=item B<disk_usage>
+
+This query collects the on-disk size of the database in bytes.
+
+=back
+
+The B<Database> block defines one PostgreSQL database for which to collect
+statistics. It accepts a single mandatory argument which specifies the
+database name. None of the other options are required. PostgreSQL will use
+default values as documented in the section "CONNECTING TO A DATABASE" in the
+L<psql(1)> manpage. However, be aware that those defaults may be influenced by
+the user collectd is run as and special environment variables. See the manpage
+for details.
+
+=over 4
+
+=item B<Host> I<hostname>
+
+Specify the hostname or IP of the PostgreSQL server to connect to. If the
+value begins with a slash, it is interpreted as the directory name in which to
+look for the UNIX domain socket.
+
+This option is also used to determine the hostname that is associated with a
+collected data set. If it has been omitted or either begins with with a slash
+or equals B<localhost> it will be replaced with the global hostname definition
+of collectd. Any other value will be passed literally to collectd when
+dispatching values. Also see the global B<Hostname> and B<FQDNLookup> options.
+
+=item B<Port> I<port>
+
+Specify the TCP port or the local UNIX domain socket file extension of the
+server.
+
+=item B<User> I<username>
+
+Specify the username to be used when connecting to the server.
+
+=item B<Password> I<password>
+
+Specify the password to be used when connecting to the server.
+
+=item B<SSLMode> I<disable>|I<allow>|I<prefer>|I<require>
+
+Specify whether to use an SSL connection when contacting the server. The
+following modes are supported:
+
+=over 4
+
+=item I<disable>
+
+Do not use SSL at all.
+
+=item I<allow>
+
+First, try to connect without using SSL. If that fails, try using SSL.
+
+=item I<prefer> (default)
+
+First, try to connect using SSL. If that fails, try without using SSL.
+
+=item I<require>
+
+Use SSL only.
+
+=back
+
+=item B<KRBSrvName> I<kerberos_service_name>
+
+Specify the Kerberos service name to use when authenticating with Kerberos 5
+or GSSAPI. See the sections "Kerberos authentication" and "GSSAPI" of the
+B<PostgreSQL Documentation> for details.
+
+=item B<Service> I<service_name>
+
+Specify the PostgreSQL service name to use for additional parameters. That
+service has to be defined in F<pg_service.conf> and holds additional
+connection parameters. See the section "The Connection Service File" in the
+B<PostgreSQL Documentation> for details.
+
+=item B<Query> I<query>
+
+Specify a I<query> which should be executed for the database connection. This
+may be any of the predefined or user-defined queries. If no such option is
+given, it defaults to "backends", "transactions", "queries", "query_plans",
+"table_states", "disk_io" and "disk_usage". Else, the specified queries are
+used only.
+
+=back
+
+=head2 Plugin C<powerdns>