man/journald.conf.xml - systemd-stable - Rivoreo Source Code Repositories

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 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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 <refentry id="journald.conf"
     xmlns:xi="http://www.w3.org/2001/XInclude">
   <refentryinfo>
     <title>journald.conf</title>
     <productname>systemd</productname>
   </refentryinfo>

   <refmeta>
     <refentrytitle>journald.conf</refentrytitle>
     <manvolnum>5</manvolnum>
   </refmeta>

   <refnamediv>
     <refname>journald.conf</refname>
     <refname>journald.conf.d</refname>
     <refpurpose>Journal service configuration files</refpurpose>
   </refnamediv>

   <refsynopsisdiv>
     <para><filename>/etc/systemd/journald.conf</filename></para>
     <para><filename>/etc/systemd/journald.conf.d/*.conf</filename></para>
     <para><filename>/run/systemd/journald.conf.d/*.conf</filename></para>
     <para><filename>/usr/lib/systemd/journald.conf.d/*.conf</filename></para>
   </refsynopsisdiv>

   <refsect1>
     <title>Description</title>

     <para>These files configure various parameters of the systemd journal service,
     <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
     See
     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     for a general description of the syntax.</para>

   </refsect1>

   <xi:include href="standard-conf.xml" xpointer="main-conf" />

   <refsect1>
     <title>Options</title>

     <para>All options are configured in the
     <literal>[Journal]</literal> section:</para>

     <variablelist class='config-directives'>

       <varlistentry>
         <term><varname>Storage=</varname></term>

         <listitem><para>Controls where to store journal data. One of
         <literal>volatile</literal>,
         <literal>persistent</literal>,
         <literal>auto</literal> and
         <literal>none</literal>. If
         <literal>volatile</literal>, journal
         log data will be stored only in memory, i.e. below the
         <filename>/run/log/journal</filename> hierarchy (which is
         created if needed). If <literal>persistent</literal>, data
         will be stored preferably on disk, i.e. below the
         <filename>/var/log/journal</filename> hierarchy (which is
         created if needed), with a fallback to
         <filename>/run/log/journal</filename> (which is created if
         needed), during early boot and if the disk is not writable.
         <literal>auto</literal> is similar to
         <literal>persistent</literal> but the directory
         <filename>/var/log/journal</filename> is not created if
         needed, so that its existence controls where log data goes.
         <literal>none</literal> turns off all storage, all log data
         received will be dropped. Forwarding to other targets, such as
         the console, the kernel log buffer, or a syslog socket will
         still work however. Defaults to
         <literal>auto</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>Compress=</varname></term>

         <listitem><para>Can take a boolean value. If enabled (the
         default), data objects that shall be stored in the journal
         and are larger than the default threshold of 512 bytes are
         compressed before they are written to the file system. It
         can also be set to a number of bytes to specify the
         compression threshold directly. Suffixes like K, M, and G
         can be used to specify larger units.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>Seal=</varname></term>

         <listitem><para>Takes a boolean value. If enabled (the
         default), and a sealing key is available (as created by
         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
         <option>--setup-keys</option> command), Forward Secure Sealing
         (FSS) for all persistent journal files is enabled. FSS is
         based on <ulink
         url="https://eprint.iacr.org/2013/397">Seekable Sequential Key
         Generators</ulink> by G. A. Marson and B. Poettering
         (doi:10.1007/978-3-642-40203-6_7) and may be used to protect
         journal files from unnoticed alteration.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>SplitMode=</varname></term>

         <listitem><para>Controls whether to split up journal files per user, either <literal>uid</literal> or
         <literal>none</literal>. Split journal files are primarily useful for access control: on UNIX/Linux access
         control is managed per file, and the journal daemon will assign users read access to their journal files. If
         <literal>uid</literal>, all regular users will each get their own journal files, and system users will log to
         the system journal. If <literal>none</literal>, journal files are not split up by user and all messages are
         instead stored in the single system journal. In this mode unprivileged users generally do not have access to
         their own log data. Note that splitting up journal files by user is only available for journals stored
         persistently. If journals are stored on volatile storage (see <varname>Storage=</varname> above), only a single
         journal file is used. Defaults to <literal>uid</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>RateLimitIntervalSec=</varname></term>
         <term><varname>RateLimitBurst=</varname></term>

         <listitem><para>Configures the rate limiting that is applied
         to all messages generated on the system. If, in the time
         interval defined by <varname>RateLimitIntervalSec=</varname>,
         more messages than specified in
         <varname>RateLimitBurst=</varname> are logged by a service,
         all further messages within the interval are dropped until the
         interval is over. A message about the number of dropped
         messages is generated. This rate limiting is applied
         per-service, so that two services which log do not interfere
         with each other's limits. Defaults to 10000 messages in 30s.
         The time specification for
         <varname>RateLimitIntervalSec=</varname> may be specified in the
         following units: <literal>s</literal>, <literal>min</literal>,
         <literal>h</literal>, <literal>ms</literal>,
         <literal>us</literal>. To turn off any kind of rate limiting,
         set either value to 0.</para>

         <para>If a service provides rate limits for itself through
         <varname>LogRateLimitIntervalSec=</varname> and/or <varname>LogRateLimitBurst=</varname>
         in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         those values will override the settings specified here.</para>
         </listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>SystemMaxUse=</varname></term>
         <term><varname>SystemKeepFree=</varname></term>
         <term><varname>SystemMaxFileSize=</varname></term>
         <term><varname>SystemMaxFiles=</varname></term>
         <term><varname>RuntimeMaxUse=</varname></term>
         <term><varname>RuntimeKeepFree=</varname></term>
         <term><varname>RuntimeMaxFileSize=</varname></term>
         <term><varname>RuntimeMaxFiles=</varname></term>

         <listitem><para>Enforce size limits on the journal files
         stored. The options prefixed with <literal>System</literal>
         apply to the journal files when stored on a persistent file
         system, more specifically
         <filename>/var/log/journal</filename>. The options prefixed
         with <literal>Runtime</literal> apply to the journal files
         when stored on a volatile in-memory file system, more
         specifically <filename>/run/log/journal</filename>. The former
         is used only when <filename>/var</filename> is mounted,
         writable, and the directory
         <filename>/var/log/journal</filename> exists. Otherwise, only
         the latter applies. Note that this means that during early
         boot and if the administrator disabled persistent logging,
         only the latter options apply, while the former apply if
         persistent logging is enabled and the system is fully booted
         up. <command>journalctl</command> and
         <command>systemd-journald</command> ignore all files with
         names not ending with <literal>.journal</literal> or
         <literal>.journal~</literal>, so only such files, located in
         the appropriate directories, are taken into account when
         calculating current disk usage.</para>

         <para><varname>SystemMaxUse=</varname> and
         <varname>RuntimeMaxUse=</varname> control how much disk space
         the journal may use up at most.
         <varname>SystemKeepFree=</varname> and
         <varname>RuntimeKeepFree=</varname> control how much disk
         space systemd-journald shall leave free for other uses.
         <command>systemd-journald</command> will respect both limits
         and use the smaller of the two values.</para>

         <para>The first pair defaults to 10% and the second to 15% of
         the size of the respective file system, but each value is
         capped to 4G. If the file system is nearly full and either
         <varname>SystemKeepFree=</varname> or
         <varname>RuntimeKeepFree=</varname> are violated when
         systemd-journald is started, the limit will be raised to the
         percentage that is actually free. This means that if there was
         enough free space before and journal files were created, and
         subsequently something else causes the file system to fill up,
         journald will stop using more space, but it will not be
         removing existing files to reduce the footprint again,
         either. Also note that only archived files are deleted to reduce the
         space occupied by journal files. This means that, in effect, there might
         still be more space used than <varname>SystemMaxUse=</varname> or
         <varname>RuntimeMaxUse=</varname> limit after a vacuuming operation is
         complete.</para>

         <para><varname>SystemMaxFileSize=</varname> and
         <varname>RuntimeMaxFileSize=</varname> control how large
         individual journal files may grow at most. This influences
         the granularity in which disk space is made available through
         rotation, i.e. deletion of historic data. Defaults to one
         eighth of the values configured with
         <varname>SystemMaxUse=</varname> and
         <varname>RuntimeMaxUse=</varname>, so that usually seven
         rotated journal files are kept as history.</para>

         <para>Specify values in bytes or use K, M, G, T, P, E as
         units for the specified sizes (equal to 1024, 1024², … bytes).
         Note that size limits are enforced synchronously when journal
         files are extended, and no explicit rotation step triggered by
         time is needed.</para>

         <para><varname>SystemMaxFiles=</varname> and
         <varname>RuntimeMaxFiles=</varname> control how many
         individual journal files to keep at most. Note that only
         archived files are deleted to reduce the number of files until
         this limit is reached; active files will stay around. This
         means that, in effect, there might still be more journal files
         around in total than this limit after a vacuuming operation is
         complete. This setting defaults to 100.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>MaxFileSec=</varname></term>

         <listitem><para>The maximum time to store entries in a single
         journal file before rotating to the next one. Normally,
         time-based rotation should not be required as size-based
         rotation with options such as
         <varname>SystemMaxFileSize=</varname> should be sufficient to
         ensure that journal files do not grow without bounds. However,
         to ensure that not too much data is lost at once when old
         journal files are deleted, it might make sense to change this
         value from the default of one month. Set to 0 to turn off this
         feature. This setting takes time values which may be suffixed
         with the units <literal>year</literal>,
         <literal>month</literal>, <literal>week</literal>,
         <literal>day</literal>, <literal>h</literal> or
         <literal>m</literal> to override the default time unit of
         seconds.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>MaxRetentionSec=</varname></term>

         <listitem><para>The maximum time to store journal entries.
         This controls whether journal files containing entries older
         than the specified time span are deleted. Normally, time-based
         deletion of old journal files should not be required as
         size-based deletion with options such as
         <varname>SystemMaxUse=</varname> should be sufficient to
         ensure that journal files do not grow without bounds. However,
         to enforce data retention policies, it might make sense to
         change this value from the default of 0 (which turns off this
         feature). This setting also takes time values which may be
         suffixed with the units <literal>year</literal>,
         <literal>month</literal>, <literal>week</literal>,
         <literal>day</literal>, <literal>h</literal> or <literal>
         m</literal> to override the default time unit of
         seconds.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>SyncIntervalSec=</varname></term>

         <listitem><para>The timeout before synchronizing journal files
         to disk. After syncing, journal files are placed in the
         OFFLINE state. Note that syncing is unconditionally done
         immediately after a log message of priority CRIT, ALERT or
         EMERG has been logged. This setting hence applies only to
         messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The
         default timeout is 5 minutes. </para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>ForwardToSyslog=</varname></term>
         <term><varname>ForwardToKMsg=</varname></term>
         <term><varname>ForwardToConsole=</varname></term>
         <term><varname>ForwardToWall=</varname></term>

         <listitem><para>Control whether log messages received by the journal daemon shall be forwarded to a
         traditional syslog daemon, to the kernel log buffer (kmsg), to the system console, or sent as wall
         messages to all logged-in users.  These options take boolean arguments. If forwarding to syslog is
         enabled but nothing reads messages from the socket, forwarding to syslog has no effect. By default,
         only forwarding to wall is enabled. These settings may be overridden at boot time with the kernel
         command line options <literal>systemd.journald.forward_to_syslog</literal>,
         <literal>systemd.journald.forward_to_kmsg</literal>,
         <literal>systemd.journald.forward_to_console</literal>, and
         <literal>systemd.journald.forward_to_wall</literal>. If the option name is specified without
         <literal>=</literal> and the following argument, true is assumed. Otherwise, the argument is parsed
         as a boolean.</para>

         <para>When forwarding to the console, the TTY to log to can be changed with
         <varname>TTYPath=</varname>, described below.</para>

         <para>When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large size for
         the log buffer, and ensure the kernel's rate-limiting applied to userspace processes is turned
         off. Specifically, add <literal>log_buf_len=8M</literal> and <literal>printk.devkmsg=on</literal> (or
         similar) to the kernel command line.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>MaxLevelStore=</varname></term>
         <term><varname>MaxLevelSyslog=</varname></term>
         <term><varname>MaxLevelKMsg=</varname></term>
         <term><varname>MaxLevelConsole=</varname></term>
         <term><varname>MaxLevelWall=</varname></term>

         <listitem><para>Controls the maximum log level of messages
         that are stored on disk, forwarded to syslog, kmsg, the
         console or wall (if that is enabled, see above). As argument,
         takes one of
         <literal>emerg</literal>,
         <literal>alert</literal>,
         <literal>crit</literal>,
         <literal>err</literal>,
         <literal>warning</literal>,
         <literal>notice</literal>,
         <literal>info</literal>,
         <literal>debug</literal>,
         or integer values in the range of 0–7 (corresponding to the
         same levels). Messages equal or below the log level specified
         are stored/forwarded, messages above are dropped. Defaults to
         <literal>debug</literal> for <varname>MaxLevelStore=</varname>
         and <varname>MaxLevelSyslog=</varname>, to ensure that the all
         messages are written to disk and forwarded to syslog. Defaults
         to
         <literal>notice</literal> for <varname>MaxLevelKMsg=</varname>,
         <literal>info</literal> for <varname>MaxLevelConsole=</varname>,
         and <literal>emerg</literal> for
         <varname>MaxLevelWall=</varname>. These settings may be
         overridden at boot time with the kernel command line options
         <literal>systemd.journald.max_level_store=</literal>,
         <literal>systemd.journald.max_level_syslog=</literal>,
         <literal>systemd.journald.max_level_kmsg=</literal>,
         <literal>systemd.journald.max_level_console=</literal>,
         <literal>systemd.journald.max_level_wall=</literal>.</para>
         </listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>ReadKMsg=</varname></term>

         <listitem><para>Takes a boolean value. If enabled (the
         default), journal reads <filename>/dev/kmsg</filename>
         messages generated by the kernel.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>TTYPath=</varname></term>

         <listitem><para>Change the console TTY to use if
         <varname>ForwardToConsole=yes</varname> is used. Defaults to
         <filename>/dev/console</filename>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>LineMax=</varname></term>

         <listitem><para>The maximum line length to permit when converting stream logs into record logs. When a systemd
         unit's standard output/error are connected to the journal via a stream socket, the data read is split into
         individual log records at newline (<literal>\n</literal>, ASCII 10) and NUL characters. If no such delimiter is
         read for the specified number of bytes a hard log record boundary is artificially inserted, breaking up overly
         long lines into multiple log records. Selecting overly large values increases the possible memory usage of the
         Journal daemon for each stream client, as in the worst case the journal daemon needs to buffer the specified
         number of bytes in memory before it can flush a new log record to disk. Also note that permitting overly large
         line maximum line lengths affects compatibility with traditional log protocols as log records might not fit
         anymore into a single <constant>AF_UNIX</constant> or <constant>AF_INET</constant> datagram. Takes a size in
         bytes. If the value is suffixed with K, M, G or T, the specified size is parsed as Kilobytes, Megabytes,
         Gigabytes, or Terabytes (with the base 1024), respectively. Defaults to 48K, which is relatively large but
         still small enough so that log records likely fit into network datagrams along with extra room for
         metadata. Note that values below 79 are not accepted and will be bumped to 79.</para></listitem>
       </varlistentry>

     </variablelist>

   </refsect1>

   <refsect1>
     <title>Forwarding to traditional syslog daemons</title>

     <para>
       Journal events can be transferred to a different logging daemon
       in two different ways. With the first method, messages are
       immediately forwarded to a socket
       (<filename>/run/systemd/journal/syslog</filename>), where the
       traditional syslog daemon can read them. This method is
       controlled by the <varname>ForwardToSyslog=</varname> option. With a
       second method, a syslog daemon behaves like a normal journal
       client, and reads messages from the journal files, similarly to
       <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
       With this, messages do not have to be read immediately,
       which allows a logging daemon which is only started late in boot
       to access all messages since the start of the system. In
       addition, full structured meta-data is available to it. This
       method of course is available only if the messages are stored in
       a journal file at all. So it will not work if
       <varname>Storage=none</varname> is set. It should be noted that
       usually the <emphasis>second</emphasis> method is used by syslog
       daemons, so the <varname>Storage=</varname> option, and not the
       <varname>ForwardToSyslog=</varname> option, is relevant for them.
     </para>
   </refsect1>

   <refsect1>
       <title>See Also</title>
       <para>
         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
       </para>
   </refsect1>

 </refentry>
	<?xml version='1.0'?> <!---nxml--->
	<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
	"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
	<!-- SPDX-License-Identifier: LGPL-2.1+ -->

	<refentry id="journald.conf"
	xmlns:xi="http://www.w3.org/2001/XInclude">
	<refentryinfo>
	<title>journald.conf</title>
	<productname>systemd</productname>
	</refentryinfo>

	<refmeta>
	<refentrytitle>journald.conf</refentrytitle>
	<manvolnum>5</manvolnum>
	</refmeta>

	<refnamediv>
	<refname>journald.conf</refname>
	<refname>journald.conf.d</refname>
	<refpurpose>Journal service configuration files</refpurpose>
	</refnamediv>

	<refsynopsisdiv>
	<para><filename>/etc/systemd/journald.conf</filename></para>
	<para><filename>/etc/systemd/journald.conf.d/*.conf</filename></para>
	<para><filename>/run/systemd/journald.conf.d/*.conf</filename></para>
	<para><filename>/usr/lib/systemd/journald.conf.d/*.conf</filename></para>
	</refsynopsisdiv>

	<refsect1>
	<title>Description</title>

	<para>These files configure various parameters of the systemd journal service,
	<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
	See
	<citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	for a general description of the syntax.</para>

	</refsect1>

	<xi:include href="standard-conf.xml" xpointer="main-conf" />

	<refsect1>
	<title>Options</title>

	<para>All options are configured in the
	<literal>[Journal]</literal> section:</para>

	<variablelist class='config-directives'>

	<varlistentry>
	<term><varname>Storage=</varname></term>

	<listitem><para>Controls where to store journal data. One of
	<literal>volatile</literal>,
	<literal>persistent</literal>,
	<literal>auto</literal> and
	<literal>none</literal>. If
	<literal>volatile</literal>, journal
	log data will be stored only in memory, i.e. below the
	<filename>/run/log/journal</filename> hierarchy (which is
	created if needed). If <literal>persistent</literal>, data
	will be stored preferably on disk, i.e. below the
	<filename>/var/log/journal</filename> hierarchy (which is
	created if needed), with a fallback to
	<filename>/run/log/journal</filename> (which is created if
	needed), during early boot and if the disk is not writable.
	<literal>auto</literal> is similar to
	<literal>persistent</literal> but the directory
	<filename>/var/log/journal</filename> is not created if
	needed, so that its existence controls where log data goes.
	<literal>none</literal> turns off all storage, all log data
	received will be dropped. Forwarding to other targets, such as
	the console, the kernel log buffer, or a syslog socket will
	still work however. Defaults to
	<literal>auto</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>Compress=</varname></term>

	<listitem><para>Can take a boolean value. If enabled (the
	default), data objects that shall be stored in the journal
	and are larger than the default threshold of 512 bytes are
	compressed before they are written to the file system. It
	can also be set to a number of bytes to specify the
	compression threshold directly. Suffixes like K, M, and G
	can be used to specify larger units.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>Seal=</varname></term>

	<listitem><para>Takes a boolean value. If enabled (the
	default), and a sealing key is available (as created by
	<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
	<option>--setup-keys</option> command), Forward Secure Sealing
	(FSS) for all persistent journal files is enabled. FSS is
	based on <ulink
	url="https://eprint.iacr.org/2013/397">Seekable Sequential Key
	Generators</ulink> by G. A. Marson and B. Poettering
	(doi:10.1007/978-3-642-40203-6_7) and may be used to protect
	journal files from unnoticed alteration.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>SplitMode=</varname></term>

	<listitem><para>Controls whether to split up journal files per user, either <literal>uid</literal> or
	<literal>none</literal>. Split journal files are primarily useful for access control: on UNIX/Linux access
	control is managed per file, and the journal daemon will assign users read access to their journal files. If
	<literal>uid</literal>, all regular users will each get their own journal files, and system users will log to
	the system journal. If <literal>none</literal>, journal files are not split up by user and all messages are
	instead stored in the single system journal. In this mode unprivileged users generally do not have access to
	their own log data. Note that splitting up journal files by user is only available for journals stored
	persistently. If journals are stored on volatile storage (see <varname>Storage=</varname> above), only a single
	journal file is used. Defaults to <literal>uid</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>RateLimitIntervalSec=</varname></term>
	<term><varname>RateLimitBurst=</varname></term>

	<listitem><para>Configures the rate limiting that is applied
	to all messages generated on the system. If, in the time
	interval defined by <varname>RateLimitIntervalSec=</varname>,
	more messages than specified in
	<varname>RateLimitBurst=</varname> are logged by a service,
	all further messages within the interval are dropped until the
	interval is over. A message about the number of dropped
	messages is generated. This rate limiting is applied
	per-service, so that two services which log do not interfere
	with each other's limits. Defaults to 10000 messages in 30s.
	The time specification for
	<varname>RateLimitIntervalSec=</varname> may be specified in the
	following units: <literal>s</literal>, <literal>min</literal>,
	<literal>h</literal>, <literal>ms</literal>,
	<literal>us</literal>. To turn off any kind of rate limiting,
	set either value to 0.</para>

	<para>If a service provides rate limits for itself through
	<varname>LogRateLimitIntervalSec=</varname> and/or <varname>LogRateLimitBurst=</varname>
	in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	those values will override the settings specified here.</para>
	</listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>SystemMaxUse=</varname></term>
	<term><varname>SystemKeepFree=</varname></term>
	<term><varname>SystemMaxFileSize=</varname></term>
	<term><varname>SystemMaxFiles=</varname></term>
	<term><varname>RuntimeMaxUse=</varname></term>
	<term><varname>RuntimeKeepFree=</varname></term>
	<term><varname>RuntimeMaxFileSize=</varname></term>
	<term><varname>RuntimeMaxFiles=</varname></term>

	<listitem><para>Enforce size limits on the journal files
	stored. The options prefixed with <literal>System</literal>
	apply to the journal files when stored on a persistent file
	system, more specifically
	<filename>/var/log/journal</filename>. The options prefixed
	with <literal>Runtime</literal> apply to the journal files
	when stored on a volatile in-memory file system, more
	specifically <filename>/run/log/journal</filename>. The former
	is used only when <filename>/var</filename> is mounted,
	writable, and the directory
	<filename>/var/log/journal</filename> exists. Otherwise, only
	the latter applies. Note that this means that during early
	boot and if the administrator disabled persistent logging,
	only the latter options apply, while the former apply if
	persistent logging is enabled and the system is fully booted
	up. <command>journalctl</command> and
	<command>systemd-journald</command> ignore all files with
	names not ending with <literal>.journal</literal> or
	<literal>.journal~</literal>, so only such files, located in
	the appropriate directories, are taken into account when
	calculating current disk usage.</para>

	<para><varname>SystemMaxUse=</varname> and
	<varname>RuntimeMaxUse=</varname> control how much disk space
	the journal may use up at most.
	<varname>SystemKeepFree=</varname> and
	<varname>RuntimeKeepFree=</varname> control how much disk
	space systemd-journald shall leave free for other uses.
	<command>systemd-journald</command> will respect both limits
	and use the smaller of the two values.</para>

	<para>The first pair defaults to 10% and the second to 15% of
	the size of the respective file system, but each value is
	capped to 4G. If the file system is nearly full and either
	<varname>SystemKeepFree=</varname> or
	<varname>RuntimeKeepFree=</varname> are violated when
	systemd-journald is started, the limit will be raised to the
	percentage that is actually free. This means that if there was
	enough free space before and journal files were created, and
	subsequently something else causes the file system to fill up,
	journald will stop using more space, but it will not be
	removing existing files to reduce the footprint again,
	either. Also note that only archived files are deleted to reduce the
	space occupied by journal files. This means that, in effect, there might
	still be more space used than <varname>SystemMaxUse=</varname> or
	<varname>RuntimeMaxUse=</varname> limit after a vacuuming operation is
	complete.</para>

	<para><varname>SystemMaxFileSize=</varname> and
	<varname>RuntimeMaxFileSize=</varname> control how large
	individual journal files may grow at most. This influences
	the granularity in which disk space is made available through
	rotation, i.e. deletion of historic data. Defaults to one
	eighth of the values configured with
	<varname>SystemMaxUse=</varname> and
	<varname>RuntimeMaxUse=</varname>, so that usually seven
	rotated journal files are kept as history.</para>

	<para>Specify values in bytes or use K, M, G, T, P, E as
	units for the specified sizes (equal to 1024, 1024², … bytes).
	Note that size limits are enforced synchronously when journal
	files are extended, and no explicit rotation step triggered by
	time is needed.</para>

	<para><varname>SystemMaxFiles=</varname> and
	<varname>RuntimeMaxFiles=</varname> control how many
	individual journal files to keep at most. Note that only
	archived files are deleted to reduce the number of files until
	this limit is reached; active files will stay around. This
	means that, in effect, there might still be more journal files
	around in total than this limit after a vacuuming operation is
	complete. This setting defaults to 100.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>MaxFileSec=</varname></term>

	<listitem><para>The maximum time to store entries in a single
	journal file before rotating to the next one. Normally,
	time-based rotation should not be required as size-based
	rotation with options such as
	<varname>SystemMaxFileSize=</varname> should be sufficient to
	ensure that journal files do not grow without bounds. However,
	to ensure that not too much data is lost at once when old
	journal files are deleted, it might make sense to change this
	value from the default of one month. Set to 0 to turn off this
	feature. This setting takes time values which may be suffixed
	with the units <literal>year</literal>,
	<literal>month</literal>, <literal>week</literal>,
	<literal>day</literal>, <literal>h</literal> or
	<literal>m</literal> to override the default time unit of
	seconds.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>MaxRetentionSec=</varname></term>

	<listitem><para>The maximum time to store journal entries.
	This controls whether journal files containing entries older
	than the specified time span are deleted. Normally, time-based
	deletion of old journal files should not be required as
	size-based deletion with options such as
	<varname>SystemMaxUse=</varname> should be sufficient to
	ensure that journal files do not grow without bounds. However,
	to enforce data retention policies, it might make sense to
	change this value from the default of 0 (which turns off this
	feature). This setting also takes time values which may be
	suffixed with the units <literal>year</literal>,
	<literal>month</literal>, <literal>week</literal>,
	<literal>day</literal>, <literal>h</literal> or <literal>
	m</literal> to override the default time unit of
	seconds.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>SyncIntervalSec=</varname></term>

	<listitem><para>The timeout before synchronizing journal files
	to disk. After syncing, journal files are placed in the
	OFFLINE state. Note that syncing is unconditionally done
	immediately after a log message of priority CRIT, ALERT or
	EMERG has been logged. This setting hence applies only to
	messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The
	default timeout is 5 minutes. </para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>ForwardToSyslog=</varname></term>
	<term><varname>ForwardToKMsg=</varname></term>
	<term><varname>ForwardToConsole=</varname></term>
	<term><varname>ForwardToWall=</varname></term>

	<listitem><para>Control whether log messages received by the journal daemon shall be forwarded to a
	traditional syslog daemon, to the kernel log buffer (kmsg), to the system console, or sent as wall
	messages to all logged-in users. These options take boolean arguments. If forwarding to syslog is
	enabled but nothing reads messages from the socket, forwarding to syslog has no effect. By default,
	only forwarding to wall is enabled. These settings may be overridden at boot time with the kernel
	command line options <literal>systemd.journald.forward_to_syslog</literal>,
	<literal>systemd.journald.forward_to_kmsg</literal>,
	<literal>systemd.journald.forward_to_console</literal>, and
	<literal>systemd.journald.forward_to_wall</literal>. If the option name is specified without
	<literal>=</literal> and the following argument, true is assumed. Otherwise, the argument is parsed
	as a boolean.</para>

	<para>When forwarding to the console, the TTY to log to can be changed with
	<varname>TTYPath=</varname>, described below.</para>

	<para>When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large size for
	the log buffer, and ensure the kernel's rate-limiting applied to userspace processes is turned
	off. Specifically, add <literal>log_buf_len=8M</literal> and <literal>printk.devkmsg=on</literal> (or
	similar) to the kernel command line.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>MaxLevelStore=</varname></term>
	<term><varname>MaxLevelSyslog=</varname></term>
	<term><varname>MaxLevelKMsg=</varname></term>
	<term><varname>MaxLevelConsole=</varname></term>
	<term><varname>MaxLevelWall=</varname></term>

	<listitem><para>Controls the maximum log level of messages
	that are stored on disk, forwarded to syslog, kmsg, the
	console or wall (if that is enabled, see above). As argument,
	takes one of
	<literal>emerg</literal>,
	<literal>alert</literal>,
	<literal>crit</literal>,
	<literal>err</literal>,
	<literal>warning</literal>,
	<literal>notice</literal>,
	<literal>info</literal>,
	<literal>debug</literal>,
	or integer values in the range of 0–7 (corresponding to the
	same levels). Messages equal or below the log level specified
	are stored/forwarded, messages above are dropped. Defaults to
	<literal>debug</literal> for <varname>MaxLevelStore=</varname>
	and <varname>MaxLevelSyslog=</varname>, to ensure that the all
	messages are written to disk and forwarded to syslog. Defaults
	to
	<literal>notice</literal> for <varname>MaxLevelKMsg=</varname>,
	<literal>info</literal> for <varname>MaxLevelConsole=</varname>,
	and <literal>emerg</literal> for
	<varname>MaxLevelWall=</varname>. These settings may be
	overridden at boot time with the kernel command line options
	<literal>systemd.journald.max_level_store=</literal>,
	<literal>systemd.journald.max_level_syslog=</literal>,
	<literal>systemd.journald.max_level_kmsg=</literal>,
	<literal>systemd.journald.max_level_console=</literal>,
	<literal>systemd.journald.max_level_wall=</literal>.</para>
	</listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>ReadKMsg=</varname></term>

	<listitem><para>Takes a boolean value. If enabled (the
	default), journal reads <filename>/dev/kmsg</filename>
	messages generated by the kernel.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>TTYPath=</varname></term>

	<listitem><para>Change the console TTY to use if
	<varname>ForwardToConsole=yes</varname> is used. Defaults to
	<filename>/dev/console</filename>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>LineMax=</varname></term>

	<listitem><para>The maximum line length to permit when converting stream logs into record logs. When a systemd
	unit's standard output/error are connected to the journal via a stream socket, the data read is split into
	individual log records at newline (<literal>\n</literal>, ASCII 10) and NUL characters. If no such delimiter is
	read for the specified number of bytes a hard log record boundary is artificially inserted, breaking up overly
	long lines into multiple log records. Selecting overly large values increases the possible memory usage of the
	Journal daemon for each stream client, as in the worst case the journal daemon needs to buffer the specified
	number of bytes in memory before it can flush a new log record to disk. Also note that permitting overly large
	line maximum line lengths affects compatibility with traditional log protocols as log records might not fit
	anymore into a single <constant>AF_UNIX</constant> or <constant>AF_INET</constant> datagram. Takes a size in
	bytes. If the value is suffixed with K, M, G or T, the specified size is parsed as Kilobytes, Megabytes,
	Gigabytes, or Terabytes (with the base 1024), respectively. Defaults to 48K, which is relatively large but
	still small enough so that log records likely fit into network datagrams along with extra room for
	metadata. Note that values below 79 are not accepted and will be bumped to 79.</para></listitem>
	</varlistentry>

	</variablelist>

	</refsect1>

	<refsect1>
	<title>Forwarding to traditional syslog daemons</title>

	<para>
	Journal events can be transferred to a different logging daemon
	in two different ways. With the first method, messages are
	immediately forwarded to a socket
	(<filename>/run/systemd/journal/syslog</filename>), where the
	traditional syslog daemon can read them. This method is
	controlled by the <varname>ForwardToSyslog=</varname> option. With a
	second method, a syslog daemon behaves like a normal journal
	client, and reads messages from the journal files, similarly to
	<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
	With this, messages do not have to be read immediately,
	which allows a logging daemon which is only started late in boot
	to access all messages since the start of the system. In
	addition, full structured meta-data is available to it. This
	method of course is available only if the messages are stored in
	a journal file at all. So it will not work if
	<varname>Storage=none</varname> is set. It should be noted that
	usually the <emphasis>second</emphasis> method is used by syslog
	daemons, so the <varname>Storage=</varname> option, and not the
	<varname>ForwardToSyslog=</varname> option, is relevant for them.
	</para>
	</refsect1>

	<refsect1>
	<title>See Also</title>
	<para>
	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	</para>
	</refsect1>

	</refentry>