1SYSTEMD.MOUNT(5) systemd.mount SYSTEMD.MOUNT(5)
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6 systemd.mount - Mount unit configuration
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9 mount.mount
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12 A unit configuration file whose name ends in ".mount" encodes
13 information about a file system mount point controlled and supervised
14 by systemd.
15 This man page lists the configuration options specific to this unit
17 type. See systemd.unit(5) for the common options of all unit
18 configuration files. The common configuration items are configured in
19 the generic "[Unit]" and "[Install]" sections. The mount specific
20 configuration options are configured in the "[Mount]" section.
21 Additional options are listed in systemd.exec(5), which define the
23 execution environment the mount(8) program is executed in, and in
24 systemd.kill(5), which define the way the processes are terminated, and
25 in systemd.resource-control(5), which configure resource control
26 settings for the processes of the service.
27 Note that the options User= and Group= are not useful for mount units.
29 systemd passes two parameters to mount(8); the values of What= and
30 Where=. When invoked in this way, mount(8) does not read any options
31 from /etc/fstab, and must be run as UID 0.
32 Mount units must be named after the mount point directories they
34 control. Example: the mount point /home/lennart must be configured in a
35 unit file home-lennart.mount. For details about the escaping logic used
36 to convert a file system path to a unit name, see systemd.unit(5). Note
37 that mount units cannot be templated, nor is possible to add multiple
38 names to a mount unit by creating additional symlinks to it.
39 Optionally, a mount unit may be accompanied by an automount unit, to
41 allow on-demand or parallelized mounting. See systemd.automount(5).
42 Mount points created at runtime (independently of unit files or
44 /etc/fstab) will be monitored by systemd and appear like any other
45 mount unit in systemd. See /proc/self/mountinfo description in proc(5).
46 Some file systems have special semantics as API file systems for
48 kernel-to-userspace and userspace-to-userspace interfaces. Some of them
49 may not be changed via mount units, and cannot be disabled. For a
50 longer discussion see API File Systems[1].
51 The systemd-mount(1) command allows creating .mount and .automount
53 units dynamically and transiently from the command line.
54
56 Implicit Dependencies
57 The following dependencies are implicitly added:
58 · If a mount unit is beneath another mount unit in the file system
60 hierarchy, both a requirement dependency and an ordering dependency
61 between both units are created automatically.
62 · Block device backed file systems automatically gain BindsTo= and
64 After= type dependencies on the device unit encapsulating the block
65 device (see below).
66 · If traditional file system quota is enabled for a mount unit,
68 automatic Wants= and Before= dependencies on
69 systemd-quotacheck.service and quotaon.service are added.
70 · Additional implicit dependencies may be added as result of
72 execution and resource control parameters as documented in
73 systemd.exec(5) and systemd.resource-control(5).
74 Default Dependencies
76 The following dependencies are added unless DefaultDependencies=no is
77 set:
78 · All mount units acquire automatic Before= and Conflicts= on
80 umount.target in order to be stopped during shutdown.
81 · Mount units referring to local file systems automatically gain an
83 After= dependency on local-fs-pre.target, and a Before= dependency
84 on local-fs.target unless nofail mount option is set.
85 · Network mount units automatically acquire After= dependencies on
87 remote-fs-pre.target, network.target and network-online.target, and
88 gain a Before= dependency on remote-fs.target unless nofail mount
89 option is set. Towards the latter a Wants= unit is added as well.
90 Mount units referring to local and network file systems are
92 distinguished by their file system type specification. In some cases
93 this is not sufficient (for example network block device based mounts,
94 such as iSCSI), in which case _netdev may be added to the mount option
95 string of the unit, which forces systemd to consider the mount unit a
96 network mount.
97
99 Mount units may either be configured via unit files, or via /etc/fstab
100 (see fstab(5) for details). Mounts listed in /etc/fstab will be
101 converted into native units dynamically at boot and when the
102 configuration of the system manager is reloaded. In general,
103 configuring mount points through /etc/fstab is the preferred approach.
104 See systemd-fstab-generator(8) for details about the conversion.
105 The NFS mount option bg for NFS background mounts as documented in
107 nfs(5) is detected by systemd-fstab-generator and the options are
108 transformed so that systemd fulfills the job-control implications of
109 that option. Specifically systemd-fstab-generator acts as though
110 "x-systemd.mount-timeout=infinity,retry=10000" was prepended to the
111 option list, and "fg,nofail" was appended. Depending on specific
112 requirements, it may be appropriate to provide some of these options
113 explicitly, or to make use of the "x-systemd.automount" option
114 described below instead of using "bg".
115 When reading /etc/fstab a few special mount options are understood by
117 systemd which influence how dependencies are created for mount points.
118 systemd will create a dependency of type Wants= or Requires= (see
119 option nofail below), from either local-fs.target or remote-fs.target,
120 depending whether the file system is local or remote.
121 x-systemd.requires=
123 Configures a Requires= and an After= dependency between the created
124 mount unit and another systemd unit, such as a device or mount
125 unit. The argument should be a unit name, or an absolute path to a
126 device node or mount point. This option may be specified more than
127 once. This option is particularly useful for mount point
128 declarations that need an additional device to be around (such as
129 an external journal device for journal file systems) or an
130 additional mount to be in place (such as an overlay file system
131 that merges multiple mount points). See After= and Requires= in
132 systemd.unit(5) for details.
133 x-systemd.before=, x-systemd.after=
135 In the created mount unit, configures a Before= or After=
136 dependency on another systemd unit, such as a mount unit. The
137 argument should be a unit name or an absolute path to a mount
138 point. This option may be specified more than once. This option is
139 particularly useful for mount point declarations with nofail option
140 that are mounted asynchronously but need to be mounted before or
141 after some unit start, for example, before local-fs.target unit.
142 See Before= and After= in systemd.unit(5) for details.
143 x-systemd.wanted-by=, x-systemd.required-by=
145 In the created mount unit, configures a WantedBy= or RequiredBy=
146 dependency on another unit. This option may be specified more than
147 once. If this is specified, the normal automatic dependencies on
148 the created mount unit, e.g., local-fs.target, are not
149 automatically created. See WantedBy= and RequiredBy= in
150 systemd.unit(5) for details.
151 x-systemd.requires-mounts-for=
153 Configures a RequiresMountsFor= dependency between the created
154 mount unit and other mount units. The argument must be an absolute
155 path. This option may be specified more than once. See
156 RequiresMountsFor= in systemd.unit(5) for details.
157 x-systemd.device-bound
159 The block device backed file system will be upgraded to BindsTo=
160 dependency. This option is only useful when mounting file systems
161 manually with mount(8) as the default dependency in this case is
162 Requires=. This option is already implied by entries in /etc/fstab
163 or by mount units.
164 x-systemd.automount
166 An automount unit will be created for the file system. See
167 systemd.automount(5) for details.
168 x-systemd.idle-timeout=
170 Configures the idle timeout of the automount unit. See
171 TimeoutIdleSec= in systemd.automount(5) for details.
172 x-systemd.device-timeout=
174 Configure how long systemd should wait for a device to show up
175 before giving up on an entry from /etc/fstab. Specify a time in
176 seconds or explicitly append a unit such as "s", "min", "h", "ms".
177 Note that this option can only be used in /etc/fstab, and will be
179 ignored when part of the Options= setting in a unit file.
180 x-systemd.mount-timeout=
182 Configure how long systemd should wait for the mount command to
183 finish before giving up on an entry from /etc/fstab. Specify a time
184 in seconds or explicitly append a unit such as "s", "min", "h",
185 "ms".
186 Note that this option can only be used in /etc/fstab, and will be
188 ignored when part of the Options= setting in a unit file.
189 See TimeoutSec= below for details.
191 x-systemd.makefs
193 The file system will be initialized on the device. If the device is
194 not "empty", i.e. it contains any signature, the operation will be
195 skipped. It is hence expected that this option remains set even
196 after the device has been initialized.
197 Note that this option can only be used in /etc/fstab, and will be
199 ignored when part of the Options= setting in a unit file.
200 See systemd-makefs@.service(8).
202 wipefs(8) may be used to remove any signatures from a block device
204 to force x-systemd.makefs to reinitialize the device.
205 x-systemd.growfs
207 The file system will be grown to occupy the full block device. If
208 the file system is already at maximum size, no action will be
209 performed. It is hence expected that this option remains set even
210 after the file system has been grown. Only certain file system
211 types are supported, see systemd-makefs@.service(8) for details.
212 Note that this option can only be used in /etc/fstab, and will be
214 ignored when part of the Options= setting in a unit file.
215 _netdev
217 Normally the file system type is used to determine if a mount is a
218 "network mount", i.e. if it should only be started after the
219 network is available. Using this option overrides this detection
220 and specifies that the mount requires network.
221 Network mount units are ordered between remote-fs-pre.target and
223 remote-fs.target, instead of local-fs-pre.target and
224 local-fs.target. They also pull in network-online.target and are
225 ordered after it and network.target.
226 noauto, auto
228 With noauto, the mount unit will not be added as a dependency for
229 local-fs.target or remote-fs.target. This means that it will not be
230 mounted automatically during boot, unless it is pulled in by some
231 other unit. The auto option has the opposite meaning and is the
232 default. Note that the noauto option has an effect on the mount
233 unit itself only — if x-systemd.automount is used (see above), then
234 the matching automount unit will still be pulled in by these
235 targets.
236 nofail
238 With nofail, this mount will be only wanted, not required, by
239 local-fs.target or remote-fs.target. Moreover the mount unit is not
240 ordered before these target units. This means that the boot will
241 continue without waiting for the mount unit and regardless whether
242 the mount point can be mounted successfully.
243 x-initrd.mount
245 An additional filesystem to be mounted in the initramfs. See
246 initrd-fs.target description in systemd.special(7).
247 If a mount point is configured in both /etc/fstab and a unit file that
249 is stored below /usr, the former will take precedence. If the unit file
250 is stored below /etc, it will take precedence. This means: native unit
251 files take precedence over traditional configuration files, but this is
252 superseded by the rule that configuration in /etc will always take
253 precedence over configuration in /usr.
254
256 Mount files must include a [Mount] section, which carries information
257 about the file system mount points it supervises. A number of options
258 that may be used in this section are shared with other unit types.
259 These options are documented in systemd.exec(5) and systemd.kill(5).
260 The options specific to the [Mount] section of mount units are the
261 following:
262 What=
264 Takes an absolute path of a device node, file or other resource to
265 mount. See mount(8) for details. If this refers to a device node, a
266 dependency on the respective device unit is automatically created.
267 (See systemd.device(5) for more information.) This option is
268 mandatory. Note that the usual specifier expansion is applied to
269 this setting, literal percent characters should hence be written as
270 "%%". If this mount is a bind mount and the specified path does not
271 exist yet it is created as directory.
272 Where=
274 Takes an absolute path of a file or directory for the mount point;
275 in particular, the destination cannot be a symbolic link. If the
276 mount point does not exist at the time of mounting, it is created
277 as directory. This string must be reflected in the unit filename.
278 (See above.) This option is mandatory.
279 Type=
281 Takes a string for the file system type. See mount(8) for details.
282 This setting is optional.
283 Options=
285 Mount options to use when mounting. This takes a comma-separated
286 list of options. This setting is optional. Note that the usual
287 specifier expansion is applied to this setting, literal percent
288 characters should hence be written as "%%".
289 SloppyOptions=
291 Takes a boolean argument. If true, parsing of the options specified
292 in Options= is relaxed, and unknown mount options are tolerated.
293 This corresponds with mount(8)'s -s switch. Defaults to off.
294 LazyUnmount=
296 Takes a boolean argument. If true, detach the filesystem from the
297 filesystem hierarchy at time of the unmount operation, and clean up
298 all references to the filesystem as soon as they are not busy
299 anymore. This corresponds with umount(8)'s -l switch. Defaults to
300 off.
301 ForceUnmount=
303 Takes a boolean argument. If true, force an unmount (in case of an
304 unreachable NFS system). This corresponds with umount(8)'s -f
305 switch. Defaults to off.
306 DirectoryMode=
308 Directories of mount points (and any parent directories) are
309 automatically created if needed. This option specifies the file
310 system access mode used when creating these directories. Takes an
311 access mode in octal notation. Defaults to 0755.
312 TimeoutSec=
314 Configures the time to wait for the mount command to finish. If a
315 command does not exit within the configured time, the mount will be
316 considered failed and be shut down again. All commands still
317 running will be terminated forcibly via SIGTERM, and after another
318 delay of this time with SIGKILL. (See KillMode= in
319 systemd.kill(5).) Takes a unit-less value in seconds, or a time
320 span value such as "5min 20s". Pass 0 to disable the timeout logic.
321 The default value is set from DefaultTimeoutStartSec= option in
322 systemd-system.conf(5).
323 Check systemd.exec(5) and systemd.kill(5) for more settings.
325
327 systemd(1), systemctl(1), systemd-system.conf(5), systemd.unit(5),
328 systemd.exec(5), systemd.kill(5), systemd.resource-control(5),
329 systemd.service(5), systemd.device(5), proc(5), mount(8), systemd-
330 fstab-generator(8), systemd.directives(7), systemd-mount(1)
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333 1. API File Systems
334 https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
335systemd 245 SYSTEMD.MOUNT(5)