NAME

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

SYNOPSIS

       /etc/systemd/journald.conf

       /etc/systemd/journald.conf.d/*.conf

       /run/systemd/journald.conf.d/*.conf

       /usr/lib/systemd/journald.conf.d/*.conf

DESCRIPTION

       These files configure various parameters of the systemd journal service, systemd-journald.service(8).

CONFIGURATION DIRECTORIES AND PRECEDENCE

       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 overrides.

       When packages need to customize the configuration, they can install configuration snippets in
       /usr/lib/systemd/*.conf.d/. Files in /etc/ are reserved for the local administrator, who may use this
       logic to override the configuration files installed by vendor packages. 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 which of
       the subdirectories they reside in. 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. 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

       All options are configured in the "[Journal]" section:

       Storage=
           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" is similar to
           "persistent" but the directory /var/log/journal is not created if needed, so that its existence
           controls where log data goes.  "none" turns off all storage, all log data received will be dropped.
           Forwarding to other targets, such as the console, the kernel log buffer, or a syslog socket will
           still work however. Defaults to "auto".

       Compress=
           Takes a boolean value. If enabled (the default), data objects that shall be stored in the journal and
           are larger than a certain threshold are compressed before they are written to the file system.

       Seal=
           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.

       SplitMode=
           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 will
           each get their own journal files, and system users will log to the system journal. 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 1000 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 0.

       SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=, RuntimeMaxUse=, RuntimeKeepFree=,
       RuntimeMaxFileSize=, RuntimeMaxFiles=
           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.

           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 needed.

           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.

       MaxFileSec=
           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 seconds.

       MaxRetentionSec=
           The maximum time to store journal entries. This controls whether journal files containing entries
           older then 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.

       SyncIntervalSec=
           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 syslog and wall is enabled. These settings may be overridden at boot time with the
           kernel command line options "systemd.journald.forward_to_syslog", "systemd.journald.forward_to_kmsg",
           "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.

       MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=, MaxLevelConsole=, MaxLevelWall=
           Controls the maximum log level of messages that are stored on disk, forwarded to syslog, kmsg, the
           console or wall (if that is enabled, see above). As argument, takes one of "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 written to disk 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=",
           "systemd.journald.max_level_syslog=", "systemd.journald.max_level_kmsg=",
           "systemd.journald.max_level_console=", "systemd.journald.max_level_wall=".

       ReadKMsg=
           Takes a boolean value. If enabled (the default), journal reads /dev/kmsg messages generated by the
           kernel.

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

       LineMax=
           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.

FORWARDING TO TRADITIONAL SYSLOG DAEMONS

       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

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

NOTES

        1. Seekable Sequential Key Generators
           https://eprint.iacr.org/2013/397

systemd 237                                                                                     JOURNALD.CONF(5)