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. One
of "uid", "login" and "none". If
"uid", all users will get each their own journal files regardless of
whether they possess a login session or not, however system users will log
into the system journal. If "login", actually logged-in users will
get each their own journal files, but users without login session and system
users will log into the system journal. If "none", journal files are
not split up by user and all messages are instead stored in the single system
journal. Note that splitting up journal files by user is only available for
journals stored persistently. If journals are stored on volatile storage (see
above), only a single journal file for all user IDs is kept. Defaults to
"uid".
RateLimitInterval=, RateLimitBurst=
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 1000 messages in 30s. 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.
SystemMaxUse=, SystemKeepFree=,
SystemMaxFileSize=, 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 maximum. 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= is violated when systemd-journald is started, the
value will be raised to 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 go
reduce footprint either.
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 (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.
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=". 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=.
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 artifically 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.