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473 lines
24 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!-- SPDX-License-Identifier: LGPL-2.1+ -->
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<refentry id="journald.conf"
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xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo>
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<title>journald.conf</title>
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<productname>systemd</productname>
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</refentryinfo>
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<refmeta>
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<refentrytitle>journald.conf</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>journald.conf</refname>
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<refname>journald.conf.d</refname>
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<refname>journald@.conf</refname>
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<refpurpose>Journal service configuration files</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename>/etc/systemd/journald.conf</filename></para>
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<para><filename>/etc/systemd/journald.conf.d/*.conf</filename></para>
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<para><filename>/run/systemd/journald.conf.d/*.conf</filename></para>
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<para><filename>/usr/lib/systemd/journald.conf.d/*.conf</filename></para>
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<para><filename>/etc/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>These files configure various parameters of the systemd journal service,
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<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
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See
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<citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for a general description of the syntax.</para>
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<para>The <command>systemd-journald</command> instance managing the default namespace is configured by
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<filename>/etc/systemd/journald.conf</filename> and associated drop-ins. Instances managing other
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namespaces read <filename>/etc/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf</filename> with
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the namespace identifier filled in. This allows each namespace to carry a distinct configuration. See
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<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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for details about journal namespaces.</para>
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</refsect1>
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<xi:include href="standard-conf.xml" xpointer="main-conf" />
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<refsect1>
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<title>Options</title>
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<para>All options are configured in the
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<literal>[Journal]</literal> section:</para>
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<variablelist class='config-directives'>
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<varlistentry>
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<term><varname>Storage=</varname></term>
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<listitem><para>Controls where to store journal data. One of <literal>volatile</literal>,
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<literal>persistent</literal>, <literal>auto</literal> and <literal>none</literal>. If
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<literal>volatile</literal>, journal log data will be stored only in memory, i.e. below the
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<filename>/run/log/journal</filename> hierarchy (which is created if needed). If
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<literal>persistent</literal>, data will be stored preferably on disk, i.e. below the
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<filename>/var/log/journal</filename> hierarchy (which is created if needed), with a fallback to
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<filename>/run/log/journal</filename> (which is created if needed), during early boot and if the disk
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is not writable. <literal>auto</literal> is similar to <literal>persistent</literal> but the
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directory <filename>/var/log/journal</filename> is not created if needed, so that its existence
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controls where log data goes. <literal>none</literal> turns off all storage, all log data received
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will be dropped. Forwarding to other targets, such as the console, the kernel log buffer, or a syslog
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socket will still work however. Defaults to <literal>auto</literal> in the default journal namespace,
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and <literal>persistent</literal> in all others.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Compress=</varname></term>
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<listitem><para>Can take a boolean value. If enabled (the
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default), data objects that shall be stored in the journal
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and are larger than the default threshold of 512 bytes are
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compressed before they are written to the file system. It
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can also be set to a number of bytes to specify the
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compression threshold directly. Suffixes like K, M, and G
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can be used to specify larger units.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>Seal=</varname></term>
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<listitem><para>Takes a boolean value. If enabled (the
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default), and a sealing key is available (as created by
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<citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
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<option>--setup-keys</option> command), Forward Secure Sealing
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(FSS) for all persistent journal files is enabled. FSS is
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based on <ulink
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url="https://eprint.iacr.org/2013/397">Seekable Sequential Key
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Generators</ulink> by G. A. Marson and B. Poettering
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(doi:10.1007/978-3-642-40203-6_7) and may be used to protect
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journal files from unnoticed alteration.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>SplitMode=</varname></term>
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<listitem><para>Controls whether to split up journal files per user, either <literal>uid</literal> or
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<literal>none</literal>. Split journal files are primarily useful for access control: on UNIX/Linux access
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control is managed per file, and the journal daemon will assign users read access to their journal files. If
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<literal>uid</literal>, all regular users (with UID outside the range of system users, dynamic service users,
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and the nobody user) will each get their own journal files, and system users will log to the system journal.
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See <ulink url="https://systemd.io/UIDS-GIDS">Users, Groups, UIDs and GIDs on systemd systems</ulink>
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for more details about UID ranges.
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If <literal>none</literal>, journal files are not split up by user and all messages are
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instead stored in the single system journal. In this mode unprivileged users generally do not have access to
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their own log data. Note that splitting up journal files by user is only available for journals stored
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persistently. If journals are stored on volatile storage (see <varname>Storage=</varname> above), only a single
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journal file is used. Defaults to <literal>uid</literal>.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>RateLimitIntervalSec=</varname></term>
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<term><varname>RateLimitBurst=</varname></term>
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<listitem><para>Configures the rate limiting that is applied
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to all messages generated on the system. If, in the time
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interval defined by <varname>RateLimitIntervalSec=</varname>,
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more messages than specified in
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<varname>RateLimitBurst=</varname> are logged by a service,
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all further messages within the interval are dropped until the
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interval is over. A message about the number of dropped
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messages is generated. This rate limiting is applied
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per-service, so that two services which log do not interfere
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with each other's limits. Defaults to 10000 messages in 30s.
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The time specification for
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<varname>RateLimitIntervalSec=</varname> may be specified in the
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following units: <literal>s</literal>, <literal>min</literal>,
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<literal>h</literal>, <literal>ms</literal>,
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<literal>us</literal>. To turn off any kind of rate limiting,
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set either value to 0.</para>
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<para>Note that the effective rate limit is multiplied with a
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factor derived from the available free disk space for the journal.
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Currently, this factor is calculated using the base 2 logarithm.</para>
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<table>
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<title>Example <varname>RateLimitBurst=</varname> rate
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modifications by the available disk space</title>
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<tgroup cols='2'>
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<colspec colname='freespace' />
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<colspec colname='multiplier' />
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<thead>
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<row>
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<entry>Available Disk Space</entry>
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<entry>Burst Multiplier</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><= 1MB</entry>
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<entry>1</entry>
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</row>
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<row>
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<entry><= 16MB</entry>
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<entry>2</entry>
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</row>
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<row>
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<entry><= 256MB</entry>
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<entry>3</entry>
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</row>
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<row>
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<entry><= 4GB</entry>
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<entry>4</entry>
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</row>
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<row>
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<entry><= 64GB</entry>
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<entry>5</entry>
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</row>
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<row>
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<entry><= 1TB</entry>
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<entry>6</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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<para>If a service provides rate limits for itself through
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<varname>LogRateLimitIntervalSec=</varname> and/or <varname>LogRateLimitBurst=</varname>
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in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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those values will override the settings specified here.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>SystemMaxUse=</varname></term>
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<term><varname>SystemKeepFree=</varname></term>
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<term><varname>SystemMaxFileSize=</varname></term>
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<term><varname>SystemMaxFiles=</varname></term>
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<term><varname>RuntimeMaxUse=</varname></term>
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<term><varname>RuntimeKeepFree=</varname></term>
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<term><varname>RuntimeMaxFileSize=</varname></term>
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<term><varname>RuntimeMaxFiles=</varname></term>
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<listitem><para>Enforce size limits on the journal files
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stored. The options prefixed with <literal>System</literal>
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apply to the journal files when stored on a persistent file
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system, more specifically
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<filename>/var/log/journal</filename>. The options prefixed
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with <literal>Runtime</literal> apply to the journal files
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when stored on a volatile in-memory file system, more
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specifically <filename>/run/log/journal</filename>. The former
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is used only when <filename>/var</filename> is mounted,
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writable, and the directory
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<filename>/var/log/journal</filename> exists. Otherwise, only
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the latter applies. Note that this means that during early
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boot and if the administrator disabled persistent logging,
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only the latter options apply, while the former apply if
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persistent logging is enabled and the system is fully booted
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up. <command>journalctl</command> and
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<command>systemd-journald</command> ignore all files with
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names not ending with <literal>.journal</literal> or
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<literal>.journal~</literal>, so only such files, located in
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the appropriate directories, are taken into account when
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calculating current disk usage.</para>
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<para><varname>SystemMaxUse=</varname> and
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<varname>RuntimeMaxUse=</varname> control how much disk space
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the journal may use up at most.
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<varname>SystemKeepFree=</varname> and
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<varname>RuntimeKeepFree=</varname> control how much disk
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space systemd-journald shall leave free for other uses.
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<command>systemd-journald</command> will respect both limits
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and use the smaller of the two values.</para>
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<para>The first pair defaults to 10% and the second to 15% of
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the size of the respective file system, but each value is
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capped to 4G. If the file system is nearly full and either
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<varname>SystemKeepFree=</varname> or
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<varname>RuntimeKeepFree=</varname> are violated when
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systemd-journald is started, the limit will be raised to the
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percentage that is actually free. This means that if there was
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enough free space before and journal files were created, and
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subsequently something else causes the file system to fill up,
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journald will stop using more space, but it will not be
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removing existing files to reduce the footprint again,
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either. Also note that only archived files are deleted to reduce the
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space occupied by journal files. This means that, in effect, there might
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still be more space used than <varname>SystemMaxUse=</varname> or
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<varname>RuntimeMaxUse=</varname> limit after a vacuuming operation is
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complete.</para>
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<para><varname>SystemMaxFileSize=</varname> and
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<varname>RuntimeMaxFileSize=</varname> control how large
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individual journal files may grow at most. This influences
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the granularity in which disk space is made available through
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rotation, i.e. deletion of historic data. Defaults to one
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eighth of the values configured with
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<varname>SystemMaxUse=</varname> and
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<varname>RuntimeMaxUse=</varname>, so that usually seven
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rotated journal files are kept as history.</para>
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<para>Specify values in bytes or use K, M, G, T, P, E as
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units for the specified sizes (equal to 1024, 1024², … bytes).
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Note that size limits are enforced synchronously when journal
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files are extended, and no explicit rotation step triggered by
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time is needed.</para>
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<para><varname>SystemMaxFiles=</varname> and
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<varname>RuntimeMaxFiles=</varname> control how many
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individual journal files to keep at most. Note that only
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archived files are deleted to reduce the number of files until
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this limit is reached; active files will stay around. This
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means that, in effect, there might still be more journal files
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around in total than this limit after a vacuuming operation is
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complete. This setting defaults to 100.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MaxFileSec=</varname></term>
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<listitem><para>The maximum time to store entries in a single
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journal file before rotating to the next one. Normally,
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time-based rotation should not be required as size-based
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rotation with options such as
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<varname>SystemMaxFileSize=</varname> should be sufficient to
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ensure that journal files do not grow without bounds. However,
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to ensure that not too much data is lost at once when old
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journal files are deleted, it might make sense to change this
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value from the default of one month. Set to 0 to turn off this
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feature. This setting takes time values which may be suffixed
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with the units <literal>year</literal>,
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<literal>month</literal>, <literal>week</literal>,
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<literal>day</literal>, <literal>h</literal> or
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<literal>m</literal> to override the default time unit of
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seconds.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>MaxRetentionSec=</varname></term>
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<listitem><para>The maximum time to store journal entries.
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This controls whether journal files containing entries older
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than the specified time span are deleted. Normally, time-based
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deletion of old journal files should not be required as
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size-based deletion with options such as
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<varname>SystemMaxUse=</varname> should be sufficient to
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ensure that journal files do not grow without bounds. However,
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to enforce data retention policies, it might make sense to
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change this value from the default of 0 (which turns off this
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feature). This setting also takes time values which may be
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suffixed with the units <literal>year</literal>,
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<literal>month</literal>, <literal>week</literal>,
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<literal>day</literal>, <literal>h</literal> or <literal>
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m</literal> to override the default time unit of
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seconds.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>SyncIntervalSec=</varname></term>
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<listitem><para>The timeout before synchronizing journal files
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to disk. After syncing, journal files are placed in the
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OFFLINE state. Note that syncing is unconditionally done
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immediately after a log message of priority CRIT, ALERT or
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EMERG has been logged. This setting hence applies only to
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messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The
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default timeout is 5 minutes. </para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>ForwardToSyslog=</varname></term>
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<term><varname>ForwardToKMsg=</varname></term>
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<term><varname>ForwardToConsole=</varname></term>
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<term><varname>ForwardToWall=</varname></term>
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<listitem><para>Control whether log messages received by the journal daemon shall be forwarded to a
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traditional syslog daemon, to the kernel log buffer (kmsg), to the system console, or sent as wall
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messages to all logged-in users. These options take boolean arguments. If forwarding to syslog is
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enabled but nothing reads messages from the socket, forwarding to syslog has no effect. By default,
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only forwarding to wall is enabled. These settings may be overridden at boot time with the kernel
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command line options <literal>systemd.journald.forward_to_syslog</literal>,
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<literal>systemd.journald.forward_to_kmsg</literal>,
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<literal>systemd.journald.forward_to_console</literal>, and
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<literal>systemd.journald.forward_to_wall</literal>. If the option name is specified without
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<literal>=</literal> and the following argument, true is assumed. Otherwise, the argument is parsed
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as a boolean.</para>
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<para>When forwarding to the console, the TTY to log to can be changed with
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<varname>TTYPath=</varname>, described below.</para>
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<para>When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large size for
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the log buffer, for example by adding <literal>log_buf_len=8M</literal> to the kernel command line.
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<command>systemd</command> will automatically disable kernel's rate-limiting applied to userspace
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processes (equivalent to setting <literal>printk.devkmsg=on</literal>).</para></listitem>
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||
</varlistentry>
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||
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||
<varlistentry>
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<term><varname>MaxLevelStore=</varname></term>
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||
<term><varname>MaxLevelSyslog=</varname></term>
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||
<term><varname>MaxLevelKMsg=</varname></term>
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||
<term><varname>MaxLevelConsole=</varname></term>
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||
<term><varname>MaxLevelWall=</varname></term>
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||
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<listitem><para>Controls the maximum log level of messages
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||
that are stored in the journal, forwarded to syslog, kmsg, the
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||
console or wall (if that is enabled, see above). As argument,
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||
takes one of
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||
<literal>emerg</literal>,
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||
<literal>alert</literal>,
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||
<literal>crit</literal>,
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||
<literal>err</literal>,
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||
<literal>warning</literal>,
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||
<literal>notice</literal>,
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||
<literal>info</literal>,
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||
<literal>debug</literal>,
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||
or integer values in the range of 0–7 (corresponding to the
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||
same levels). Messages equal or below the log level specified
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||
are stored/forwarded, messages above are dropped. Defaults to
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||
<literal>debug</literal> for <varname>MaxLevelStore=</varname>
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||
and <varname>MaxLevelSyslog=</varname>, to ensure that the all
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||
messages are stored in the journal and forwarded to syslog.
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||
Defaults to
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||
<literal>notice</literal> for <varname>MaxLevelKMsg=</varname>,
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||
<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
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||
<literal>systemd.journald.max_level_store=</literal>,
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||
<literal>systemd.journald.max_level_syslog=</literal>,
|
||
<literal>systemd.journald.max_level_kmsg=</literal>,
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||
<literal>systemd.journald.max_level_console=</literal>,
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||
<literal>systemd.journald.max_level_wall=</literal>.</para>
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||
</listitem>
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||
</varlistentry>
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||
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||
<varlistentry>
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||
<term><varname>ReadKMsg=</varname></term>
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||
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||
<listitem><para>Takes a boolean value. If enabled <command>systemd-journal</command> processes
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||
<filename>/dev/kmsg</filename> messages generated by the kernel. In the default journal namespace
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||
this option is enabled by default, it is disabled in all others.</para></listitem>
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||
</varlistentry>
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||
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||
<varlistentry>
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||
<term><varname>TTYPath=</varname></term>
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||
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||
<listitem><para>Change the console TTY to use if
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||
<varname>ForwardToConsole=yes</varname> is used. Defaults to
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||
<filename>/dev/console</filename>.</para></listitem>
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||
</varlistentry>
|
||
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||
<varlistentry>
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||
<term><varname>LineMax=</varname></term>
|
||
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||
<listitem><para>The maximum line length to permit when converting stream logs into record logs. When a systemd
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||
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>
|