1JOURNALD.CONF(5) journald.conf JOURNALD.CONF(5)
2
6 journald.conf, journald.conf.d - Journal service configuration files
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9 /etc/systemd/journald.conf
10 /etc/systemd/journald.conf.d/*.conf
12 /run/systemd/journald.conf.d/*.conf
14 /usr/lib/systemd/journald.conf.d/*.conf
16
18 These files configure various parameters of the systemd journal
19 service, systemd-journald.service(8). See systemd.syntax(5) for a
20 general description of the syntax.
21
23 The default configuration is defined during compilation, so a
24 configuration file is only needed when it is necessary to deviate from
25 those defaults. By default, the configuration file in /etc/systemd/
26 contains commented out entries showing the defaults as a guide to the
27 administrator. This file can be edited to create local overrides.
28 When packages need to customize the configuration, they can install
30 configuration snippets in /usr/lib/systemd/*.conf.d/. Files in /etc/
31 are reserved for the local administrator, who may use this logic to
32 override the configuration files installed by vendor packages. The main
33 configuration file is read before any of the configuration directories,
34 and has the lowest precedence; entries in a file in any configuration
35 directory override entries in the single configuration file. Files in
36 the *.conf.d/ configuration subdirectories are sorted by their filename
37 in lexicographic order, regardless of which of the subdirectories they
38 reside in. When multiple files specify the same option, for options
39 which accept just a single value, the entry in the file with the
40 lexicographically latest name takes precedence. For options which
41 accept a list of values, entries are collected as they occur in files
42 sorted lexicographically. It is recommended to prefix all filenames in
43 those subdirectories with a two-digit number and a dash, to simplify
44 the ordering of the files.
45 To disable a configuration file supplied by the vendor, the recommended
47 way is to place a symlink to /dev/null in the configuration directory
48 in /etc/, with the same filename as the vendor configuration file.
49
51 All options are configured in the "[Journal]" section:
52 Storage=
54 Controls where to store journal data. One of "volatile",
55 "persistent", "auto" and "none". If "volatile", journal log data
56 will be stored only in memory, i.e. below the /run/log/journal
57 hierarchy (which is created if needed). If "persistent", data will
58 be stored preferably on disk, i.e. below the /var/log/journal
59 hierarchy (which is created if needed), with a fallback to
60 /run/log/journal (which is created if needed), during early boot
61 and if the disk is not writable. "auto" is similar to "persistent"
62 but the directory /var/log/journal is not created if needed, so
63 that its existence controls where log data goes. "none" turns off
64 all storage, all log data received will be dropped. Forwarding to
65 other targets, such as the console, the kernel log buffer, or a
66 syslog socket will still work however. Defaults to "auto".
67 Compress=
69 Can take a boolean value. If enabled (the default), data objects
70 that shall be stored in the journal and are larger than the default
71 threshold of 512 bytes are compressed before they are written to
72 the file system. It can also be set to a number of bytes to specify
73 the compression threshold directly. Suffixes like K, M, and G can
74 be used to specify larger units.
75 Seal=
77 Takes a boolean value. If enabled (the default), and a sealing key
78 is available (as created by journalctl(1)'s --setup-keys command),
79 Forward Secure Sealing (FSS) for all persistent journal files is
80 enabled. FSS is based on Seekable Sequential Key Generators[1] by
81 G. A. Marson and B. Poettering (doi:10.1007/978-3-642-40203-6_7)
82 and may be used to protect journal files from unnoticed alteration.
83 SplitMode=
85 Controls whether to split up journal files per user, either "uid"
86 or "none". Split journal files are primarily useful for access
87 control: on UNIX/Linux access control is managed per file, and the
88 journal daemon will assign users read access to their journal
89 files. If "uid", all regular users will each get their own journal
90 files, and system users will log to the system journal. If "none",
91 journal files are not split up by user and all messages are instead
92 stored in the single system journal. In this mode unprivileged
93 users generally do not have access to their own log data. Note that
94 splitting up journal files by user is only available for journals
95 stored persistently. If journals are stored on volatile storage
96 (see Storage= above), only a single journal file is used. Defaults
97 to "uid".
98 RateLimitIntervalSec=, RateLimitBurst=
100 Configures the rate limiting that is applied to all messages
101 generated on the system. If, in the time interval defined by
102 RateLimitIntervalSec=, more messages than specified in
103 RateLimitBurst= are logged by a service, all further messages
104 within the interval are dropped until the interval is over. A
105 message about the number of dropped messages is generated. This
106 rate limiting is applied per-service, so that two services which
107 log do not interfere with each other's limits. Defaults to 10000
108 messages in 30s. The time specification for RateLimitIntervalSec=
109 may be specified in the following units: "s", "min", "h", "ms",
110 "us". To turn off any kind of rate limiting, set either value to 0.
111 SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=,
113 RuntimeMaxUse=, RuntimeKeepFree=, RuntimeMaxFileSize=, RuntimeMaxFiles=
114 Enforce size limits on the journal files stored. The options
115 prefixed with "System" apply to the journal files when stored on a
116 persistent file system, more specifically /var/log/journal. The
117 options prefixed with "Runtime" apply to the journal files when
118 stored on a volatile in-memory file system, more specifically
119 /run/log/journal. The former is used only when /var is mounted,
120 writable, and the directory /var/log/journal exists. Otherwise,
121 only the latter applies. Note that this means that during early
122 boot and if the administrator disabled persistent logging, only the
123 latter options apply, while the former apply if persistent logging
124 is enabled and the system is fully booted up. journalctl and
125 systemd-journald ignore all files with names not ending with
126 ".journal" or ".journal~", so only such files, located in the
127 appropriate directories, are taken into account when calculating
128 current disk usage.
129 SystemMaxUse= and RuntimeMaxUse= control how much disk space the
131 journal may use up at most. SystemKeepFree= and RuntimeKeepFree=
132 control how much disk space systemd-journald shall leave free for
133 other uses. systemd-journald will respect both limits and use the
134 smaller of the two values.
135 The first pair defaults to 10% and the second to 15% of the size of
137 the respective file system, but each value is capped to 4G. If the
138 file system is nearly full and either SystemKeepFree= or
139 RuntimeKeepFree= are violated when systemd-journald is started, the
140 limit will be raised to the percentage that is actually free. This
141 means that if there was enough free space before and journal files
142 were created, and subsequently something else causes the file
143 system to fill up, journald will stop using more space, but it will
144 not be removing existing files to reduce the footprint again,
145 either.
146 SystemMaxFileSize= and RuntimeMaxFileSize= control how large
148 individual journal files may grow at most. This influences the
149 granularity in which disk space is made available through rotation,
150 i.e. deletion of historic data. Defaults to one eighth of the
151 values configured with SystemMaxUse= and RuntimeMaxUse=, so that
152 usually seven rotated journal files are kept as history.
153 Specify values in bytes or use K, M, G, T, P, E as units for the
155 specified sizes (equal to 1024, 1024², ... bytes). Note that size
156 limits are enforced synchronously when journal files are extended,
157 and no explicit rotation step triggered by time is needed.
158 SystemMaxFiles= and RuntimeMaxFiles= control how many individual
160 journal files to keep at most. Note that only archived files are
161 deleted to reduce the number of files until this limit is reached;
162 active files will stay around. This means that, in effect, there
163 might still be more journal files around in total than this limit
164 after a vacuuming operation is complete. This setting defaults to
165 100.
166 MaxFileSec=
168 The maximum time to store entries in a single journal file before
169 rotating to the next one. Normally, time-based rotation should not
170 be required as size-based rotation with options such as
171 SystemMaxFileSize= should be sufficient to ensure that journal
172 files do not grow without bounds. However, to ensure that not too
173 much data is lost at once when old journal files are deleted, it
174 might make sense to change this value from the default of one
175 month. Set to 0 to turn off this feature. This setting takes time
176 values which may be suffixed with the units "year", "month",
177 "week", "day", "h" or "m" to override the default time unit of
178 seconds.
179 MaxRetentionSec=
181 The maximum time to store journal entries. This controls whether
182 journal files containing entries older then the specified time span
183 are deleted. Normally, time-based deletion of old journal files
184 should not be required as size-based deletion with options such as
185 SystemMaxUse= should be sufficient to ensure that journal files do
186 not grow without bounds. However, to enforce data retention
187 policies, it might make sense to change this value from the default
188 of 0 (which turns off this feature). This setting also takes time
189 values which may be suffixed with the units "year", "month",
190 "week", "day", "h" or " m" to override the default time unit of
191 seconds.
192 SyncIntervalSec=
194 The timeout before synchronizing journal files to disk. After
195 syncing, journal files are placed in the OFFLINE state. Note that
196 syncing is unconditionally done immediately after a log message of
197 priority CRIT, ALERT or EMERG has been logged. This setting hence
198 applies only to messages of the levels ERR, WARNING, NOTICE, INFO,
199 DEBUG. The default timeout is 5 minutes.
200 ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=, ForwardToWall=
202 Control whether log messages received by the journal daemon shall
203 be forwarded to a traditional syslog daemon, to the kernel log
204 buffer (kmsg), to the system console, or sent as wall messages to
205 all logged-in users. These options take boolean arguments. If
206 forwarding to syslog is enabled but nothing reads messages from the
207 socket, forwarding to syslog has no effect. By default, only
208 forwarding to wall is enabled. These settings may be overridden at
209 boot time with the kernel command line options
210 "systemd.journald.forward_to_syslog",
211 "systemd.journald.forward_to_kmsg",
212 "systemd.journald.forward_to_console", and
213 "systemd.journald.forward_to_wall". If the option name is specified
214 without "=" and the following argument, true is assumed. Otherwise,
215 the argument is parsed as a boolean. When forwarding to the
216 console, the TTY to log to can be changed with TTYPath=, described
217 below.
218 MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=, MaxLevelConsole=,
220 MaxLevelWall=
221 Controls the maximum log level of messages that are stored on disk,
222 forwarded to syslog, kmsg, the console or wall (if that is enabled,
223 see above). As argument, takes one of "emerg", "alert", "crit",
224 "err", "warning", "notice", "info", "debug", or integer values in
225 the range of 0–7 (corresponding to the same levels). Messages equal
226 or below the log level specified are stored/forwarded, messages
227 above are dropped. Defaults to "debug" for MaxLevelStore= and
228 MaxLevelSyslog=, to ensure that the all messages are written to
229 disk and forwarded to syslog. Defaults to "notice" for
230 MaxLevelKMsg=, "info" for MaxLevelConsole=, and "emerg" for
231 MaxLevelWall=. These settings may be overridden at boot time with
232 the kernel command line options
233 "systemd.journald.max_level_store=",
234 "systemd.journald.max_level_syslog=",
235 "systemd.journald.max_level_kmsg=",
236 "systemd.journald.max_level_console=",
237 "systemd.journald.max_level_wall=".
238 ReadKMsg=
240 Takes a boolean value. If enabled (the default), journal reads
241 /dev/kmsg messages generated by the kernel.
242 TTYPath=
244 Change the console TTY to use if ForwardToConsole=yes is used.
245 Defaults to /dev/console.
246 LineMax=
248 The maximum line length to permit when converting stream logs into
249 record logs. When a systemd unit's standard output/error are
250 connected to the journal via a stream socket, the data read is
251 split into individual log records at newline ("\n", ASCII 10) and
252 NUL characters. If no such delimiter is read for the specified
253 number of bytes a hard log record boundary is artificially
254 inserted, breaking up overly long lines into multiple log records.
255 Selecting overly large values increases the possible memory usage
256 of the Journal daemon for each stream client, as in the worst case
257 the journal daemon needs to buffer the specified number of bytes in
258 memory before it can flush a new log record to disk. Also note that
259 permitting overly large line maximum line lengths affects
260 compatibility with traditional log protocols as log records might
261 not fit anymore into a single AF_UNIX or AF_INET datagram. Takes a
262 size in bytes. If the value is suffixed with K, M, G or T, the
263 specified size is parsed as Kilobytes, Megabytes, Gigabytes, or
264 Terabytes (with the base 1024), respectively. Defaults to 48K,
265 which is relatively large but still small enough so that log
266 records likely fit into network datagrams along with extra room for
267 metadata. Note that values below 79 are not accepted and will be
268 bumped to 79.
269
271 Journal events can be transferred to a different logging daemon in two
272 different ways. With the first method, messages are immediately
273 forwarded to a socket (/run/systemd/journal/syslog), where the
274 traditional syslog daemon can read them. This method is controlled by
275 the ForwardToSyslog= option. With a second method, a syslog daemon
276 behaves like a normal journal client, and reads messages from the
277 journal files, similarly to journalctl(1). With this, messages do not
278 have to be read immediately, which allows a logging daemon which is
279 only started late in boot to access all messages since the start of the
280 system. In addition, full structured meta-data is available to it. This
281 method of course is available only if the messages are stored in a
282 journal file at all. So it will not work if Storage=none is set. It
283 should be noted that usually the second method is used by syslog
284 daemons, so the Storage= option, and not the ForwardToSyslog= option,
285 is relevant for them.
286
288 systemd(1), systemd-journald.service(8), journalctl(1),
289 systemd.journal-fields(7), systemd-system.conf(5)
290
292 1. Seekable Sequential Key Generators
293 https://eprint.iacr.org/2013/397
294systemd 239 JOURNALD.CONF(5)