journald.conf.d(5) — Linux manual page


JOURNALD.CONF(5)                journald.conf               JOURNALD.CONF(5)

NAME         top

       journald.conf, journald.conf.d, journald@.conf - Journal service
       configuration files

SYNOPSIS         top






DESCRIPTION         top

       These files configure various parameters of the systemd journal
       service, systemd-journald.service(8). See systemd.syntax(7) for a
       general description of the syntax.

       The systemd-journald instance managing the default namespace is
       configured by /etc/systemd/journald.conf and associated drop-ins.
       Instances managing other namespaces read
       /etc/systemd/journald@NAMESPACE.conf with the namespace identifier
       filled in. This allows each namespace to carry a distinct
       configuration. See systemd-journald.service(8) for details about
       journal namespaces.


       The default configuration is defined during compilation, so a
       configuration file is only needed when it is necessary to deviate
       from those defaults. By default, the configuration file in
       /etc/systemd/ contains commented out entries showing the defaults as
       a guide to the administrator. This file can be edited to create local

       When packages need to customize the configuration, they can install
       configuration snippets in /usr/lib/systemd/*.conf.d/ or
       /usr/local/lib/systemd/*.conf.d/. The main configuration file is read
       before any of the configuration directories, and has the lowest
       precedence; entries in a file in any configuration directory override
       entries in the single configuration file. Files in the *.conf.d/
       configuration subdirectories are sorted by their filename in
       lexicographic order, regardless of in which of the subdirectories
       they reside. When multiple files specify the same option, for options
       which accept just a single value, the entry in the file with the
       lexicographically latest name takes precedence. For options which
       accept a list of values, entries are collected as they occur in files
       sorted lexicographically.

       Files in /etc/ are reserved for the local administrator, who may use
       this logic to override the configuration files installed by vendor
       packages. It is recommended to prefix all filenames in those
       subdirectories with a two-digit number and a dash, to simplify the
       ordering of the files.

       To disable a configuration file supplied by the vendor, the
       recommended way is to place a symlink to /dev/null in the
       configuration directory in /etc/, with the same filename as the
       vendor configuration file.

OPTIONS         top

       All options are configured in the [Journal] section:

           Controls where to store journal data. One of "volatile",
           "persistent", "auto" and "none". If "volatile", journal log data
           will be stored only in memory, i.e. below the /run/log/journal
           hierarchy (which is created if needed). If "persistent", data
           will be stored preferably on disk, i.e. below the
           /var/log/journal hierarchy (which is created if needed), with a
           fallback to /run/log/journal (which is created if needed), during
           early boot and if the disk is not writable.  "auto" behaves like
           "persistent" if the /var/log/journal directory exists, and
           "volatile" otherwise (the existence of the directory controls the
           storage mode).  "none" turns off all storage, all log data
           received will be dropped (but forwarding to other targets, such
           as the console, the kernel log buffer, or a syslog socket will
           still work). Defaults to "auto" in the default journal namespace,
           and "persistent" in all others.

           Note that when this option is changed to "volatile", existing
           persistent data is not removed. In the other direction,
           journalctl(1) with the --flush option may be used to move
           volatile data to persistent storage.

           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.

           Takes a boolean value. If enabled (the default), and a sealing
           key is available (as created by journalctl(1)'s --setup-keys
           command), Forward Secure Sealing (FSS) for all persistent journal
           files is enabled. FSS is based on Seekable Sequential Key
           Generators[1] 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.

           Controls whether to split up journal files per user, either "uid"
           or "none". 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 "uid", all regular users (with UID outside the range of
           system users, dynamic service users, and the nobody user) will
           each get their own journal files, and system users will log to
           the system journal. See Users, Groups, UIDs and GIDs on systemd
           systems[2] for more details about UID ranges. If "none", 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 Storage= above), only a single journal file is used.
           Defaults to "uid".

       RateLimitIntervalSec=, RateLimitBurst=
           Configures the rate limiting that is applied to all messages
           generated on the system. If, in the time interval defined by
           RateLimitIntervalSec=, more messages than specified in
           RateLimitBurst= 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 RateLimitIntervalSec=
           may be specified in the following units: "s", "min", "h", "ms",
           "us". To turn off any kind of rate limiting, set either value to

           Note that the effective rate limit is multiplied by a factor
           derived from the available free disk space for the journal.
           Currently, this factor is calculated using the base 2 logarithm.

           Table 1. Example RateLimitBurst= rate modifications by the
           available disk space
           │Available Disk Space Burst Multiplier │
           │<= 1MB               │ 1                │
           │<= 16MB              │ 2                │
           │<= 256MB             │ 3                │
           │<= 4GB               │ 4                │
           │<= 64GB              │ 5                │
           │<= 1TB               │ 6                │
           If a service provides rate limits for itself through
           LogRateLimitIntervalSec= and/or LogRateLimitBurst= in
           systemd.exec(5), those values will override the settings
           specified here.

       SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=,
       RuntimeMaxUse=, RuntimeKeepFree=, RuntimeMaxFileSize=,
           Enforce size limits on the journal files stored. The options
           prefixed with "System" apply to the journal files when stored on
           a persistent file system, more specifically /var/log/journal. The
           options prefixed with "Runtime" apply to the journal files when
           stored on a volatile in-memory file system, more specifically
           /run/log/journal. The former is used only when /var/ is mounted,
           writable, and the directory /var/log/journal 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.  journalctl
           and systemd-journald ignore all files with names not ending with
           ".journal" or ".journal~", so only such files, located in the
           appropriate directories, are taken into account when calculating
           current disk usage.

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

           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 SystemKeepFree= or
           RuntimeKeepFree= 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 SystemMaxUse=
           or RuntimeMaxUse= limit after a vacuuming operation is complete.

           SystemMaxFileSize= and RuntimeMaxFileSize= 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 SystemMaxUse= and RuntimeMaxUse=,
           so that usually seven rotated journal files are kept as history.

           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

           SystemMaxFiles= and RuntimeMaxFiles= 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.

           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
           SystemMaxFileSize= 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 "year", "month",
           "week", "day", "h" or "m" to override the default time unit of

           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 SystemMaxUse= 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
           "year", "month", "week", "day", "h" or " m" to override the
           default time unit of seconds.

           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.

       ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=, ForwardToWall=
           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
           "systemd.journald.forward_to_console", and
           "systemd.journald.forward_to_wall". If the option name is
           specified without "=" and the following argument, true is
           assumed. Otherwise, the argument is parsed as a boolean.

           When forwarding to the console, the TTY to log to can be changed
           with TTYPath=, described below.

           When forwarding to the kernel log buffer (kmsg), make sure to
           select a suitably large size for the log buffer, for example by
           adding "log_buf_len=8M" to the kernel command line.  systemd will
           automatically disable kernel's rate-limiting applied to userspace
           processes (equivalent to setting "printk.devkmsg=on").

       MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=, MaxLevelConsole=,
           Controls the maximum log level of messages that are stored in the
           journal, forwarded to syslog, kmsg, the console or wall (if that
           is enabled, see above). As argument, takes one of "emerg",
           "alert", "crit", "err", "warning", "notice", "info", "debug", 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 "debug"
           for MaxLevelStore= and MaxLevelSyslog=, to ensure that the all
           messages are stored in the journal and forwarded to syslog.
           Defaults to "notice" for MaxLevelKMsg=, "info" for
           MaxLevelConsole=, and "emerg" for MaxLevelWall=. These settings
           may be overridden at boot time with the kernel command line
           options "systemd.journald.max_level_store=",

           Takes a boolean value. If enabled systemd-journal processes
           /dev/kmsg messages generated by the kernel. In the default
           journal namespace this option is enabled by default, it is
           disabled in all others.

           Takes a boolean value. If enabled systemd-journal will turn on
           kernel auditing on start-up. If disabled it will turn it off. If
           unset it will neither enable nor disable it, leaving the previous
           state unchanged. Note that this option does not control whether
           systemd-journald collects generated audit records, it just
           controls whether it tells the kernel to generate them. This means
           if another tool turns on auditing even if systemd-journald left
           it off, it will still collect the generated messages. Defaults to

           Change the console TTY to use if ForwardToConsole=yes is used.
           Defaults to /dev/console.

           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 ("\n", 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 AF_UNIX or
           AF_INET 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.


       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 (/run/systemd/journal/syslog), where the
       traditional syslog daemon can read them. This method is controlled by
       the ForwardToSyslog= option. With a second method, a syslog daemon
       behaves like a normal journal client, and reads messages from the
       journal files, similarly to journalctl(1). 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 Storage=none
       is set. It should be noted that usually the second method is used by
       syslog daemons, so the Storage= option, and not the ForwardToSyslog=
       option, is relevant for them.

SEE ALSO         top

       systemd(1), systemd-journald.service(8), journalctl(1),
       systemd.journal-fields(7), systemd-system.conf(5)

NOTES         top

        1. Seekable Sequential Key Generators

        2. Users, Groups, UIDs and GIDs on systemd systems

COLOPHON         top

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       report for this manual page, see
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systemd 247                                                 JOURNALD.CONF(5)

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