man/journald.conf.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="journald.conf"
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8   <refentryinfo>
   9     <title>journald.conf</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>journald.conf</refentrytitle>
  15     <manvolnum>5</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>journald.conf</refname>
  20     <refname>journald.conf.d</refname>
  21     <refname>journald@.conf</refname>
  22     <refpurpose>Journal service configuration files</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <para><simplelist>
  27       <member><filename>/etc/systemd/journald.conf</filename></member>
  28       <member><filename>/run/systemd/journald.conf</filename></member>
  29       <member><filename>/usr/lib/systemd/journald.conf</filename></member>
  30       <member><filename>/etc/systemd/journald.conf.d/*.conf</filename></member>
  31       <member><filename>/run/systemd/journald.conf.d/*.conf</filename></member>
  32       <member><filename>/usr/lib/systemd/journald.conf.d/*.conf</filename></member>
  33       <member><filename>/etc/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf</filename></member>
  34       <member><filename>/etc/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf.d/*.conf</filename></member>
  35       <member><filename>/run/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf.d/*.conf</filename></member>
  36       <member><filename>/usr/lib/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf.d/*.conf</filename></member>
  37     </simplelist></para>
  38   </refsynopsisdiv>
  39
  40   <refsect1>
  41     <title>Description</title>
  42
  43     <para>These files configure various parameters of the systemd journal service,
  44     <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  45     See
  46     <citerefentry><refentrytitle>systemd.syntax</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  47     for a general description of the syntax.</para>
  48
  49     <para>The <command>systemd-journald</command> instance managing the default namespace is configured by
  50     <filename>/etc/systemd/journald.conf</filename> and associated drop-ins. Instances managing other
  51     namespaces read <filename>/etc/systemd/journald@<replaceable>NAMESPACE</replaceable>.conf</filename>
  52     and associated drop-ins with the namespace identifier filled in. This allows each namespace to carry
  53     a distinct configuration. See
  54     <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  55     for details about journal namespaces.</para>
  56   </refsect1>
  57
  58   <xi:include href="standard-conf.xml" xpointer="main-conf" />
  59
  60   <refsect1>
  61     <title>Options</title>
  62
  63     <para>All options are configured in the
  64     [Journal] section:</para>
  65
  66     <variablelist class='config-directives'>
  67
  68       <varlistentry>
  69         <term><varname>Storage=</varname></term>
  70
  71         <listitem><para>Controls where to store journal data. One of <literal>volatile</literal>,
  72         <literal>persistent</literal>, <literal>auto</literal> and <literal>none</literal>. If
  73         <literal>volatile</literal>, journal log data will be stored only in memory, i.e. below the
  74         <filename>/run/log/journal</filename> hierarchy (which is created if needed). If
  75         <literal>persistent</literal>, data will be stored preferably on disk, i.e. below the
  76         <filename>/var/log/journal</filename> hierarchy (which is created if needed), with a fallback to
  77         <filename>/run/log/journal</filename> (which is created if needed), during early boot and if the disk
  78         is not writable. <literal>auto</literal> behaves like <literal>persistent</literal> if the
  79         <filename>/var/log/journal</filename> directory exists, and <literal>volatile</literal> otherwise
  80         (the existence of the directory controls the storage mode). <literal>none</literal> turns off all
  81         storage, all log data received will be dropped (but forwarding to other targets, such as the console,
  82         the kernel log buffer, or a syslog socket will still work). Defaults to <literal>auto</literal> in
  83         the default journal namespace, and <literal>persistent</literal> in all others.</para>
  84
  85         <para>Note that journald will initially use volatile storage, until a call to
  86         <command>journalctl --flush</command> (or sending <constant>SIGUSR1</constant> to journald) will cause
  87         it to switch to persistent logging (under the conditions mentioned above). This is done automatically
  88         on boot via <literal>systemd-journal-flush.service</literal>.</para>
  89
  90         <para>Note that when this option is changed to <literal>volatile</literal>, existing persistent data
  91         is not removed. In the other direction,
  92         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> with
  93         the <option>--flush</option> option may be used to move volatile data to persistent storage.</para>
  94
  95         <para>When journal namespacing (see <varname>LogNamespace=</varname> in
  96         <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>) is
  97         used, setting <varname>Storage=</varname> to <literal>volatile</literal> or <literal>auto</literal>
  98         will not have an effect on the creation of the per-namespace logs directory in
  99         <filename>/var/log/journal/</filename>, as the <filename>systemd-journald@.service</filename> service
 100         file by default carries <varname>LogsDirectory=</varname>. To turn that off, add a unit file drop-in
 101         file that sets <varname>LogsDirectory=</varname> to an empty string.</para>
 102
 103         <para>Note that per-user journal files are not supported unless persistent storage is enabled, thus
 104         making <command>journalctl --user</command> unavailable.</para>
 105
 106         <xi:include href="version-info.xml" xpointer="v186"/>
 107         </listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <term><varname>Compress=</varname></term>
 112
 113         <listitem><para>Can take a boolean value. If enabled (the
 114         default), data objects that shall be stored in the journal
 115         and are larger than the default threshold of 512 bytes are
 116         compressed before they are written to the file system. It
 117         can also be set to a number of bytes to specify the
 118         compression threshold directly. Suffixes like K, M, and G
 119         can be used to specify larger units.</para></listitem>
 120       </varlistentry>
 121
 122       <varlistentry>
 123         <term><varname>Seal=</varname></term>
 124
 125         <listitem><para>Takes a boolean value. If enabled (the
 126         default), and a sealing key is available (as created by
 127         <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
 128         <option>--setup-keys</option> command), Forward Secure Sealing
 129         (FSS) for all persistent journal files is enabled. FSS is
 130         based on <ulink
 131         url="https://eprint.iacr.org/2013/397">Seekable Sequential Key
 132         Generators</ulink> by G. A. Marson and B. Poettering
 133         (doi:10.1007/978-3-642-40203-6_7) and may be used to protect
 134         journal files from unnoticed alteration.</para>
 135
 136         <xi:include href="version-info.xml" xpointer="v189"/></listitem>
 137       </varlistentry>
 138
 139       <varlistentry>
 140         <term><varname>SplitMode=</varname></term>
 141
 142         <listitem><para>Controls whether to split up journal files per user, either <literal>uid</literal> or
 143         <literal>none</literal>. Split journal files are primarily useful for access control: on UNIX/Linux access
 144         control is managed per file, and the journal daemon will assign users read access to their journal files. If
 145         <literal>uid</literal>, all regular users (with UID outside the range of system users, dynamic service users,
 146         and the nobody user) will each get their own journal files, and system users will log to the system journal.
 147         See <ulink url="https://systemd.io/UIDS-GIDS">Users, Groups, UIDs and GIDs on systemd systems</ulink>
 148         for more details about UID ranges.
 149         If <literal>none</literal>, journal files are not split up by user and all messages are
 150         instead stored in the single system journal. In this mode unprivileged users generally do not have access to
 151         their own log data. Note that splitting up journal files by user is only available for journals stored
 152         persistently. If journals are stored on volatile storage (see <varname>Storage=</varname> above), only a single
 153         journal file is used. Defaults to <literal>uid</literal>.</para>
 154
 155         <xi:include href="version-info.xml" xpointer="v190"/></listitem>
 156       </varlistentry>
 157
 158       <varlistentry>
 159         <term><varname>RateLimitIntervalSec=</varname></term>
 160         <term><varname>RateLimitBurst=</varname></term>
 161
 162         <listitem><para>Configures the rate limiting that is applied
 163         to all messages generated on the system. If, in the time
 164         interval defined by <varname>RateLimitIntervalSec=</varname>,
 165         more messages than specified in
 166         <varname>RateLimitBurst=</varname> are logged by a service,
 167         all further messages within the interval are dropped until the
 168         interval is over. A message about the number of dropped
 169         messages is generated. This rate limiting is applied
 170         per-service, so that two services which log do not interfere
 171         with each other's limits. Defaults to 10000 messages in 30s.
 172         The time specification for
 173         <varname>RateLimitIntervalSec=</varname> may be specified in the
 174         following units: <literal>s</literal>, <literal>min</literal>,
 175         <literal>h</literal>, <literal>ms</literal>,
 176         <literal>us</literal>. To turn off any kind of rate limiting,
 177         set either value to 0.</para>
 178
 179         <para>Note that the effective rate limit is multiplied by a
 180         factor derived from the available free disk space for the journal.
 181         Currently, this factor is calculated using the base 2 logarithm.</para>
 182
 183         <table>
 184           <title>Example <varname>RateLimitBurst=</varname> rate
 185             modifications by the available disk space</title>
 186           <tgroup cols='2'>
 187             <colspec colname='freespace' />
 188             <colspec colname='multiplier' />
 189             <thead>
 190               <row>
 191                 <entry>Available Disk Space</entry>
 192                 <entry>Burst Multiplier</entry>
 193               </row>
 194             </thead>
 195             <tbody>
 196               <row>
 197                 <entry>&lt;= 1MB</entry>
 198                 <entry>1</entry>
 199               </row>
 200               <row>
 201                 <entry>&lt;= 16MB</entry>
 202                 <entry>2</entry>
 203               </row>
 204               <row>
 205                 <entry>&lt;= 256MB</entry>
 206                 <entry>3</entry>
 207               </row>
 208               <row>
 209                 <entry>&lt;= 4GB</entry>
 210                 <entry>4</entry>
 211               </row>
 212               <row>
 213                 <entry>&lt;= 64GB</entry>
 214                 <entry>5</entry>
 215               </row>
 216               <row>
 217                 <entry>&lt;= 1TB</entry>
 218                 <entry>6</entry>
 219               </row>
 220             </tbody>
 221           </tgroup>
 222         </table>
 223
 224         <para>If a service provides rate limits for itself through
 225         <varname>LogRateLimitIntervalSec=</varname> and/or <varname>LogRateLimitBurst=</varname>
 226         in <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 227         those values will override the settings specified here.</para>
 228         </listitem>
 229       </varlistentry>
 230
 231       <varlistentry>
 232         <term><varname>SystemMaxUse=</varname></term>
 233         <term><varname>SystemKeepFree=</varname></term>
 234         <term><varname>SystemMaxFileSize=</varname></term>
 235         <term><varname>SystemMaxFiles=</varname></term>
 236         <term><varname>RuntimeMaxUse=</varname></term>
 237         <term><varname>RuntimeKeepFree=</varname></term>
 238         <term><varname>RuntimeMaxFileSize=</varname></term>
 239         <term><varname>RuntimeMaxFiles=</varname></term>
 240
 241         <listitem><para>Enforce size limits on the journal files
 242         stored. The options prefixed with <literal>System</literal>
 243         apply to the journal files when stored on a persistent file
 244         system, more specifically
 245         <filename>/var/log/journal</filename>. The options prefixed
 246         with <literal>Runtime</literal> apply to the journal files
 247         when stored on a volatile in-memory file system, more
 248         specifically <filename>/run/log/journal</filename>. The former
 249         is used only when <filename>/var/</filename> is mounted,
 250         writable, and the directory
 251         <filename>/var/log/journal</filename> exists. Otherwise, only
 252         the latter applies. Note that this means that during early
 253         boot and if the administrator disabled persistent logging,
 254         only the latter options apply, while the former apply if
 255         persistent logging is enabled and the system is fully booted
 256         up. <command>journalctl</command> and
 257         <command>systemd-journald</command> ignore all files with
 258         names not ending with <literal>.journal</literal> or
 259         <literal>.journal~</literal>, so only such files, located in
 260         the appropriate directories, are taken into account when
 261         calculating current disk usage.</para>
 262
 263         <para><varname>SystemMaxUse=</varname> and
 264         <varname>RuntimeMaxUse=</varname> control how much disk space
 265         the journal may use up at most.
 266         <varname>SystemKeepFree=</varname> and
 267         <varname>RuntimeKeepFree=</varname> control how much disk
 268         space systemd-journald shall leave free for other uses.
 269         <command>systemd-journald</command> will respect both limits
 270         and use the smaller of the two values.</para>
 271
 272         <para>The first pair defaults to 10% and the second to 15% of
 273         the size of the respective file system, but each value is
 274         capped to 4G. If the file system is nearly full and either
 275         <varname>SystemKeepFree=</varname> or
 276         <varname>RuntimeKeepFree=</varname> are violated when
 277         systemd-journald is started, the limit will be raised to the
 278         percentage that is actually free. This means that if there was
 279         enough free space before and journal files were created, and
 280         subsequently something else causes the file system to fill up,
 281         journald will stop using more space, but it will not be
 282         removing existing files to reduce the footprint again,
 283         either. Also note that only archived files are deleted to reduce the
 284         space occupied by journal files. This means that, in effect, there might
 285         still be more space used than <varname>SystemMaxUse=</varname> or
 286         <varname>RuntimeMaxUse=</varname> limit after a vacuuming operation is
 287         complete.</para>
 288
 289         <para><varname>SystemMaxFileSize=</varname> and <varname>RuntimeMaxFileSize=</varname> control how
 290         large individual journal files may grow at most. This influences the granularity in which disk space
 291         is made available through rotation, i.e. deletion of historic data. Defaults to one eighth of the
 292         values configured with <varname>SystemMaxUse=</varname> and <varname>RuntimeMaxUse=</varname> capped
 293         to 128M, so that usually seven rotated journal files are kept as history. If the journal compact
 294         mode is enabled (enabled by default), the maximum file size is capped to 4G.</para>
 295
 296         <para>Specify values in bytes or use K, M, G, T, P, E as units for the specified sizes (equal to
 297         1024, 1024², … bytes). Note that size limits are enforced synchronously when journal files are
 298         extended, and no explicit rotation step triggered by time is needed.</para>
 299
 300         <para><varname>SystemMaxFiles=</varname> and
 301         <varname>RuntimeMaxFiles=</varname> control how many
 302         individual journal files to keep at most. Note that only
 303         archived files are deleted to reduce the number of files until
 304         this limit is reached; active files will stay around. This
 305         means that, in effect, there might still be more journal files
 306         around in total than this limit after a vacuuming operation is
 307         complete. This setting defaults to 100.</para></listitem>
 308       </varlistentry>
 309
 310       <varlistentry>
 311         <term><varname>MaxFileSec=</varname></term>
 312
 313         <listitem><para>The maximum time to store entries in a single
 314         journal file before rotating to the next one. Normally,
 315         time-based rotation should not be required as size-based
 316         rotation with options such as
 317         <varname>SystemMaxFileSize=</varname> should be sufficient to
 318         ensure that journal files do not grow without bounds. However,
 319         to ensure that not too much data is lost at once when old
 320         journal files are deleted, it might make sense to change this
 321         value from the default of one month. Set to 0 to turn off this
 322         feature. This setting takes time values which may be suffixed
 323         with the units <literal>year</literal>,
 324         <literal>month</literal>, <literal>week</literal>,
 325         <literal>day</literal>, <literal>h</literal> or
 326         <literal>m</literal> to override the default time unit of
 327         seconds.</para>
 328
 329         <xi:include href="version-info.xml" xpointer="v195"/></listitem>
 330       </varlistentry>
 331
 332       <varlistentry>
 333         <term><varname>MaxRetentionSec=</varname></term>
 334
 335         <listitem><para>The maximum time to store journal entries.
 336         This controls whether journal files containing entries older
 337         than the specified time span are deleted. Normally, time-based
 338         deletion of old journal files should not be required as
 339         size-based deletion with options such as
 340         <varname>SystemMaxUse=</varname> should be sufficient to
 341         ensure that journal files do not grow without bounds. However,
 342         to enforce data retention policies, it might make sense to
 343         change this value from the default of 0 (which turns off this
 344         feature). This setting also takes time values which may be
 345         suffixed with the units <literal>year</literal>,
 346         <literal>month</literal>, <literal>week</literal>,
 347         <literal>day</literal>, <literal>h</literal> or <literal>
 348         m</literal> to override the default time unit of
 349         seconds.</para>
 350
 351         <xi:include href="version-info.xml" xpointer="v195"/></listitem>
 352       </varlistentry>
 353
 354       <varlistentry>
 355         <term><varname>SyncIntervalSec=</varname></term>
 356
 357         <listitem><para>The timeout before synchronizing journal files
 358         to disk. After syncing, journal files are placed in the
 359         OFFLINE state. Note that syncing is unconditionally done
 360         immediately after a log message of priority CRIT, ALERT or
 361         EMERG has been logged. This setting hence applies only to
 362         messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The
 363         default timeout is 5 minutes. </para>
 364
 365         <xi:include href="version-info.xml" xpointer="v199"/></listitem>
 366       </varlistentry>
 367
 368       <varlistentry>
 369         <term><varname>ForwardToSyslog=</varname></term>
 370         <term><varname>ForwardToKMsg=</varname></term>
 371         <term><varname>ForwardToConsole=</varname></term>
 372         <term><varname>ForwardToWall=</varname></term>
 373         <term><varname>ForwardToSocket=</varname></term>
 374
 375         <listitem><para>Control whether log messages received by the journal daemon shall be forwarded to a
 376         traditional syslog daemon, to the kernel log buffer (kmsg), to the system console, sent as wall
 377         messages to all logged-in users or sent over a socket. These options take boolean arguments except
 378         for <literal>ForwardToSocket=</literal> which takes an address instead. If forwarding
 379         to syslog is enabled but nothing reads messages from the socket, forwarding to syslog has no effect. By default,
 380         only forwarding to wall is enabled. These settings may be overridden at boot time with the kernel
 381         command line options <literal>systemd.journald.forward_to_syslog</literal>,
 382         <literal>systemd.journald.forward_to_kmsg</literal>,
 383         <literal>systemd.journald.forward_to_console</literal>, and
 384         <literal>systemd.journald.forward_to_wall</literal>. If the option name is specified without
 385         <literal>=</literal> and the following argument, true is assumed. Otherwise, the argument is parsed
 386         as a boolean.</para>
 387
 388         <para>The socket forwarding address can be specified with the credential
 389         <literal>journal.forward_to_socket</literal>. The following socket types are supported:</para>
 390
 391         <para><simplelist type="inline">
 392           <member><constant>AF_INET</constant> (e.g. <literal>192.168.0.11:4444</literal>)</member>
 393           <member><constant>AF_INET6</constant> (e.g. <literal>[2001:db8::ff00:42:8329]:4444</literal>)</member>
 394           <member><constant>AF_UNIX</constant> (e.g. <literal>/run/host/journal/socket</literal>)</member>
 395           <member><constant>AF_VSOCK</constant> (e.g. <literal>vsock:2:1234</literal>)</member>
 396         </simplelist></para>
 397
 398         <para>When forwarding to the console, the TTY to log to can be changed with
 399         <varname>TTYPath=</varname>, described below.</para>
 400
 401         <para>When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large size for
 402         the log buffer, for example by adding <literal>log_buf_len=8M</literal> to the kernel command line.
 403         <command>systemd</command> will automatically disable kernel's rate-limiting applied to userspace
 404         processes (equivalent to setting <literal>printk.devkmsg=on</literal>).</para>
 405
 406         <para>When forwarding over a socket the <ulink url="https://systemd.io/JOURNAL_EXPORT_FORMATS/#journal-export-format">
 407         Journal Export Format</ulink> is used when sending over the wire.  Notably this includes the metadata
 408         field <varname>__REALTIME_TIMESTAMP</varname> so that
 409         <command>systemd-journal-remote</command> (see
 410         <citerefentry><refentrytitle>systemd-journal-remote.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
 411         can be used to receive the forwarded journal entries.</para>
 412
 413         <para>Note: Forwarding is performed synchronously within journald, and may significantly affect its
 414         performance.  This is particularly relevant when using ForwardToConsole=yes in cloud environments,
 415         where the console is often a slow, virtual serial port.
 416         Since journald is implemented as a conventional single-process daemon, forwarding to a completely
 417         hung console will block journald. This can have a cascading effect resulting in any services synchronously
 418         logging to the blocked journal also becoming blocked.  Unless actively debugging/developing something, it's
 419         generally preferable to setup a <command>journalctl --follow</command> style service redirected to the
 420         console, instead of ForwardToConsole=yes, for production use.</para>
 421         </listitem>
 422
 423         <para>Note: Using <varname>ForwardToSocket=</varname> over IPv4/IPv6 links can be very slow due to the synchronous nature of the sockets.
 424         Take care to ensure your link is a low-latency local link if possible. Typically IP networking is not available everywhere
 425         journald runs, e.g. in the initrd during boot. Consider using <constant>AF_VSOCK</constant>/<constant>AF_UNIX</constant> sockets for this if possible.
 426         </para>
 427       </varlistentry>
 428
 429       <varlistentry>
 430         <term><varname>MaxLevelStore=</varname></term>
 431         <term><varname>MaxLevelSyslog=</varname></term>
 432         <term><varname>MaxLevelKMsg=</varname></term>
 433         <term><varname>MaxLevelConsole=</varname></term>
 434         <term><varname>MaxLevelWall=</varname></term>
 435         <term><varname>MaxLevelSocket=</varname></term>
 436
 437         <listitem><para>Controls the maximum log level of messages that are stored in the journal, forwarded
 438         to syslog, kmsg, the console, the wall, or a socket (if that is enabled, see above).  As argument,
 439         takes one of <literal>emerg</literal>, <literal>alert</literal>, <literal>crit</literal>,
 440         <literal>err</literal>, <literal>warning</literal>, <literal>notice</literal>,
 441         <literal>info</literal>, <literal>debug</literal>, or integer values in the range of 0–7
 442         (corresponding to the same levels). Messages equal or below the log level specified are
 443         stored/forwarded, messages above are dropped. Defaults to <literal>debug</literal> for
 444         <varname>MaxLevelStore=</varname>, <varname>MaxLevelSyslog=</varname> and
 445         <varname>MaxLevelSocket=</varname>, to ensure that the all messages are stored in the journal,
 446         forwarded to syslog and the socket if one exists.  Defaults to <literal>notice</literal> for
 447         <varname>MaxLevelKMsg=</varname>, <literal>info</literal> for <varname>MaxLevelConsole=</varname>,
 448         and <literal>emerg</literal> for <varname>MaxLevelWall=</varname>. These settings may be overridden
 449         at boot time with the kernel command line options
 450         <literal>systemd.journald.max_level_store=</literal>,
 451         <literal>systemd.journald.max_level_syslog=</literal>,
 452         <literal>systemd.journald.max_level_kmsg=</literal>,
 453         <literal>systemd.journald.max_level_console=</literal>,
 454         <literal>systemd.journald.max_level_wall=</literal>,
 455         <literal>systemd.journald.max_level_socket=</literal>.</para>
 456
 457         <xi:include href="version-info.xml" xpointer="v185"/>
 458         </listitem>
 459       </varlistentry>
 460
 461       <varlistentry>
 462         <term><varname>ReadKMsg=</varname></term>
 463
 464         <listitem><para>Takes a boolean value. If enabled <command>systemd-journal</command> processes
 465         <filename>/dev/kmsg</filename> messages generated by the kernel. In the default journal namespace
 466         this option is enabled by default, it is disabled in all others.</para>
 467
 468         <xi:include href="version-info.xml" xpointer="v235"/></listitem>
 469       </varlistentry>
 470
 471       <varlistentry>
 472         <term><varname>Audit=</varname></term>
 473
 474         <listitem><para>Takes a boolean value. If enabled <command>systemd-journald</command> will turn on
 475         kernel auditing on start-up. If disabled it will turn it off. If unset it will neither enable nor
 476         disable it, leaving the previous state unchanged.  This means if another tool turns on auditing even
 477         if <command>systemd-journald</command> left it off, it will still collect the generated
 478         messages. Defaults to on.</para>
 479
 480         <para>Note that this option does not control whether <command>systemd-journald</command> collects
 481         generated audit records, it just controls whether it tells the kernel to generate them. If you need
 482         to prevent <command>systemd-journald</command> from collecting the generated messages, the socket
 483         unit <literal>systemd-journald-audit.socket</literal> can be disabled and in this case this setting
 484         is without effect.</para>
 485
 486         <xi:include href="version-info.xml" xpointer="v246"/>
 487         </listitem>
 488       </varlistentry>
 489
 490       <varlistentry>
 491         <term><varname>TTYPath=</varname></term>
 492
 493         <listitem><para>Change the console TTY to use if
 494         <varname>ForwardToConsole=yes</varname> is used. Defaults to
 495         <filename>/dev/console</filename>.</para>
 496
 497         <xi:include href="version-info.xml" xpointer="v185"/></listitem>
 498       </varlistentry>
 499
 500       <varlistentry>
 501         <term><varname>LineMax=</varname></term>
 502
 503         <listitem><para>The maximum line length to permit when converting stream logs into record logs. When a systemd
 504         unit's standard output/error are connected to the journal via a stream socket, the data read is split into
 505         individual log records at newline (<literal>\n</literal>, ASCII 10) and <constant>NUL</constant> characters. If no such delimiter is
 506         read for the specified number of bytes a hard log record boundary is artificially inserted, breaking up overly
 507         long lines into multiple log records. Selecting overly large values increases the possible memory usage of the
 508         Journal daemon for each stream client, as in the worst case the journal daemon needs to buffer the specified
 509         number of bytes in memory before it can flush a new log record to disk. Also note that permitting overly large
 510         line maximum line lengths affects compatibility with traditional log protocols as log records might not fit
 511         anymore into a single <constant>AF_UNIX</constant> or <constant>AF_INET</constant> datagram. Takes a size in
 512         bytes. If the value is suffixed with K, M, G or T, the specified size is parsed as Kilobytes, Megabytes,
 513         Gigabytes, or Terabytes (with the base 1024), respectively. Defaults to 48K, which is relatively large but
 514         still small enough so that log records likely fit into network datagrams along with extra room for
 515         metadata. Note that values below 79 are not accepted and will be bumped to 79.</para>
 516
 517         <xi:include href="version-info.xml" xpointer="v235"/></listitem>
 518       </varlistentry>
 519
 520     </variablelist>
 521
 522   </refsect1>
 523
 524   <refsect1>
 525     <title>Forwarding to traditional syslog daemons</title>
 526
 527     <para>
 528       Journal events can be transferred to a different logging daemon
 529       in two different ways. With the first method, messages are
 530       immediately forwarded to a socket
 531       (<filename>/run/systemd/journal/syslog</filename>), where the
 532       traditional syslog daemon can read them. This method is
 533       controlled by the <varname>ForwardToSyslog=</varname> option. With a
 534       second method, a syslog daemon behaves like a normal journal
 535       client, and reads messages from the journal files, similarly to
 536       <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
 537       With this, messages do not have to be read immediately,
 538       which allows a logging daemon which is only started late in boot
 539       to access all messages since the start of the system. In
 540       addition, full structured meta-data is available to it. This
 541       method of course is available only if the messages are stored in
 542       a journal file at all. So it will not work if
 543       <varname>Storage=none</varname> is set. It should be noted that
 544       usually the <emphasis>second</emphasis> method is used by syslog
 545       daemons, so the <varname>Storage=</varname> option, and not the
 546       <varname>ForwardToSyslog=</varname> option, is relevant for them.
 547     </para>
 548   </refsect1>
 549
 550   <refsect1>
 551       <title>See Also</title>
 552       <para><simplelist type="inline">
 553         <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
 554         <member><citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
 555         <member><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
 556         <member><citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
 557         <member><citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
 558       </simplelist></para>
 559   </refsect1>
 560
 561 </refentry>