journald.conf

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 daemon will still work however. Defaults to auto.

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 with the XZ compression algorithm before they are written to the file system.

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.

Controls whether to split up journal files per user. One of login, uid and none. If login each logged in user will get his own journal files, but systemd user IDs will log into the system journal. If uid any user ID will get his own journal files regardless whether it belongs to a system service or refers to a real logged in user. If none journal files are not split up per-user and all messages are stored in the single system journal. Note that splitting up journal files per-user is only available of journals are stored persistently. If journals are stored on volatile storage (see above) only a single journal file for all user IDs is kept. Defaults to login.

Configures the rate limiting that is applied to all messages generated on the system. If in the time interval defined by RateLimitInterval= 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 200 messages in 10s. The time specification for RateLimitInterval= 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.

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. SystemMaxUse= and RuntimeMaxUse= control how much disk space the journal may use up at maximum. Defaults to 10% of the size of the respective file system. SystemKeepFree= and RuntimeKeepFree= control how much disk space the journal shall always leave free for other uses if less than the disk space configured in SystemMaxUse= and RuntimeMaxUse= is available. Defaults to 15% of the size of the respective file system. SystemMaxFileSize= and RuntimeMaxFileSize= control how large individual journal files may grow at maximum. 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. Note that size limits are enforced synchronously to journal files as they are extended, and need no explicit rotation step triggered by time.

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 don't 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, m to override the default time unit of seconds.

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 don't 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, m to override the default time unit of seconds.

The timeout before syncing journal data to disk. After syncing journal files have OFFLINE state. Default timeout is 5 minutes.

Control whether log messages received by the journal daemon shall be forwarded to a traditional syslog daemon, to the kernel log buffer (kmsg), or to the system console. These options take boolean arguments. If forwarding to syslog is enabled but no syslog daemon is running the respective option has no effect. By default only forwarding to syslog 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= and systemd.journald.forward_to_console=.

Controls the maximum log level of messages that are stored on disk, forwarded to syslog, kmsg or the console (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= and info for MaxLevelConsole=.

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