journald.conf, journald.conf.d — Journal service configuration files
These files configure various parameters of the systemd journal service, systemd-journald.service(8).
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. If multiple files
specify the same option, the entry in the file with the
lexicographically latest name takes precedence. 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
All options are configured in the
Controls where to store journal data. One of
log data will be stored only in memory, i.e. below the
/run/log/journal hierarchy (which is
created if needed). If "
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
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.
Takes a boolean value. If enabled (the
default), and a sealing key is available (as created by
--setup-keys command), Forward Secure Sealing
(FSS) for all persistent journal files is enabled. FSS is
based on Seekable Sequential Key
Generators 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 "
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 "
Configures the rate limiting that is applied
to all messages generated on the system. If, in the time
interval defined by
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: "
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 "
apply to the journal files when stored on a persistent file
system, more specifically
/var/log/journal. The options prefixed
Runtime" apply to the journal files
when stored on a volatile in-memory file system, more
/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~", so only such files, located in
the appropriate directories, are taken into account when
calculating current disk usage.
RuntimeMaxUse= control how much disk space
the journal may use up at most.
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
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,
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
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.
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 "
m" to override the default time unit of
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 "
h" or "
m" to override the default time unit of
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.
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_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
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
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
MaxLevelSyslog=, to ensure that the all
messages are written to disk and forwarded to syslog. Defaults
MaxLevelWall=. These settings may be
overridden at boot time with the kernel command line options
Change the console TTY to use if
ForwardToConsole=yes is used. Defaults to
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
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.