SYSTEMD.MOUNT(5) systemd.mount SYSTEMD.MOUNT(5)
NAME
systemd.mount - Mount unit configuration
SYNOPSIS
mount.mount
DESCRIPTION
A unit configuration file whose name ends in ".mount" encodes
information about a file system mount point controlled and supervised by
systemd.
This man page lists the configuration options specific to this unit
type. See systemd.unit(5) for the common options of all unit
configuration files. The common configuration items are configured in
the generic [Unit] and [Install] sections. The mount specific
configuration options are configured in the [Mount] section.
Additional options are listed in systemd.exec(5), which define the
execution environment the mount(8) program is executed in, and in
systemd.kill(5), which define the way the processes are terminated, and
in systemd.resource-control(5), which configure resource control
settings for the processes of the service.
Note that the options User= and Group= are not useful for mount units.
systemd passes two parameters to mount(8); the values of What= and
Where=. When invoked in this way, mount(8) does not read any options
from /etc/fstab, and must be run as UID 0.
Mount units must be named after the mount point directories they
control. Example: the mount point /home/lennart must be configured in a
unit file home-lennart.mount. For details about the escaping logic used
to convert a file system path to a unit name, see systemd.unit(5). Note
that mount units cannot be templated, nor is possible to add multiple
names to a mount unit by creating symlinks to its unit file.
Optionally, a mount unit may be accompanied by an automount unit, to
allow on-demand or parallelized mounting. See systemd.automount(5).
Mount points created at runtime (independently of unit files or
/etc/fstab) will be monitored by systemd and appear like any other mount
unit in systemd. See /proc/self/mountinfo description in proc(5).
Some file systems have special semantics as API file systems for
kernel-to-userspace and userspace-to-userspace interfaces. Some of them
may not be changed via mount units, and cannot be disabled. For a longer
discussion see API File Systems[1].
The systemd-mount(1) command allows creating .mount and .automount units
dynamically and transiently from the command line.
AUTOMATIC DEPENDENCIES
Implicit Dependencies
The following dependencies are implicitly added:
• If a mount unit is beneath another mount unit in the file system
hierarchy, both a requirement dependency and an ordering dependency
between both units are created automatically.
• Block device backed file systems automatically gain Requires=,
StopPropagatedFrom=, and After= type dependencies on the device unit
encapsulating the block device (see x-systemd.device-bound= for
details).
• If traditional file system quota is enabled for a mount unit,
automatic Wants= and Before= dependencies on
systemd-quotacheck.service and quotaon.service are added.
• Additional implicit dependencies may be added as result of execution
and resource control parameters as documented in systemd.exec(5) and
systemd.resource-control(5).
Default Dependencies
The following dependencies are added unless DefaultDependencies=no is
set:
• All mount units acquire automatic Before= and Conflicts= on
umount.target in order to be stopped during shutdown.
• Mount units referring to local file systems automatically gain an
After= dependency on local-fs-pre.target, and a Before= dependency
on local-fs.target unless one or more mount options among nofail,
x-systemd.wanted-by=, and x-systemd.required-by= is set. See below
for detailed information.
Additionally, an After= dependency on swap.target is added when the
file system type is "tmpfs".
• Network mount units automatically acquire After= dependencies on
remote-fs-pre.target, network.target, plus After= and Wants=
dependencies on network-online.target, and a Before= dependency on
remote-fs.target, unless one or more mount options among nofail,
x-systemd.wanted-by=, and x-systemd.required-by= is set.
Mount units referring to local and network file systems are
distinguished by their file system type specification. In some cases
this is not sufficient (for example network block device based mounts,
such as iSCSI), in which case _netdev may be added to the mount option
string of the unit, which forces systemd to consider the mount unit a
network mount.
FSTAB
Mount units may either be configured via unit files, or via /etc/fstab
(see fstab(5) for details). Mounts listed in /etc/fstab will be
converted into native units dynamically at boot and when the
configuration of the system manager is reloaded. In general, configuring
mount points through /etc/fstab is the preferred approach to manage
mounts for humans. For tooling, writing mount units should be preferred
over editing /etc/fstab. See systemd-fstab-generator(8) for details
about the conversion from /etc/fstab to mount units.
The NFS mount option bg for NFS background mounts as documented in
nfs(5) is detected by systemd-fstab-generator and the options are
transformed so that systemd fulfills the job-control implications of
that option. Specifically systemd-fstab-generator acts as though
"x-systemd.mount-timeout=infinity,retry=10000" was prepended to the
option list, and "fg,nofail" was appended. Depending on specific
requirements, it may be appropriate to provide some of these options
explicitly, or to make use of the "x-systemd.automount" option described
below instead of using "bg".
When reading /etc/fstab a few special mount options are understood by
systemd which influence how dependencies are created for mount points.
systemd will create a dependency of type Wants= or Requires= (see option
nofail below), from either local-fs.target or remote-fs.target,
depending whether the file system is local or remote.
x-systemd.requires=
Configures a Requires= and an After= dependency between the created
mount unit and another systemd unit, such as a device or mount unit.
The argument should be a unit name, or an absolute path to a device
node or mount point. This option may be specified more than once.
This option is particularly useful for mount point declarations that
need an additional device to be around (such as an external journal
device for journal file systems) or an additional mount to be in
place (such as an overlay file system that merges multiple mount
points). See After= and Requires= in systemd.unit(5) for details.
Note that this option always applies to the created mount unit only
regardless whether x-systemd.automount has been specified.
Added in version 220.
x-systemd.wants=
Configures a Wants= and an After= dependency between the created
mount unit and another systemd unit, similar to the
x-systemd.requires= option.
Added in version 257.
x-systemd.before=, x-systemd.after=
In the created mount unit, configures a Before= or After= dependency
on another systemd unit, such as a mount unit. The argument should
be a unit name or an absolute path to a mount point. This option may
be specified more than once. This option is particularly useful for
mount point declarations with nofail option that are mounted
asynchronously but need to be mounted before or after some unit
start, for example, before local-fs.target unit. See Before= and
After= in systemd.unit(5) for details.
Note that these options always apply to the created mount unit only
regardless whether x-systemd.automount has been specified.
Added in version 233.
x-systemd.wanted-by=, x-systemd.required-by=
In the created mount unit, configures a WantedBy= or RequiredBy=
dependency on another unit. This option may be specified more than
once. If this is specified, the default dependencies (see above)
other than umount.target on the created mount unit, e.g.
local-fs.target, are not automatically created. Hence it is likely
that some ordering dependencies need to be set up manually through
x-systemd.before= and x-systemd.after=. See WantedBy= and
RequiredBy= in systemd.unit(5) for details.
Added in version 245.
x-systemd.wants-mounts-for=, x-systemd.requires-mounts-for=
Configures a RequiresMountsFor= or WantsMountsFor= dependency
between the created mount unit and other mount units. The argument
must be an absolute path. This option may be specified more than
once. See RequiresMountsFor= or WantsMountsFor= in systemd.unit(5)
for details.
Added in version 220.
x-systemd.device-bound=
Takes a boolean argument. If true or no argument, a BindsTo=
dependency on the backing device is set. If false, the mount unit is
not stopped no matter whether the backing device is still present.
This is useful when the file system is backed by volume managers. If
not set, and the mount comes from unit fragments, i.e. generated
from /etc/fstab by systemd-fstab-generator(8) or loaded from a
manually configured mount unit, a combination of Requires= and
StopPropagatedFrom= dependencies is set on the backing device,
otherwise only Requires= is used.
Added in version 233.
x-systemd.automount
An automount unit will be created for the file system. See
systemd.automount(5) for details.
Added in version 215.
x-systemd.idle-timeout=
Configures the idle timeout of the automount unit. See
TimeoutIdleSec= in systemd.automount(5) for details.
Added in version 220.
x-systemd.device-timeout=
Configure how long systemd should wait for a device to show up
before giving up on an entry from /etc/fstab. Specify a time in
seconds or explicitly append a unit such as "s", "min", "h", "ms".
Note that this option can only be used in /etc/fstab, and will be
ignored when part of the Options= setting in a unit file.
Added in version 215.
x-systemd.mount-timeout=
Configure how long systemd should wait for the mount command to
finish before giving up on an entry from /etc/fstab. Specify a time
in seconds or explicitly append a unit such as "s", "min", "h",
"ms".
Note that this option can only be used in /etc/fstab, and will be
ignored when part of the Options= setting in a unit file.
See TimeoutSec= below for details.
Added in version 233.
x-systemd.makefs
The file system will be initialized on the device. If the device is
not "empty", i.e. it contains any signature, the operation will be
skipped. It is hence expected that this option remains set even
after the device has been initialized.
Note that this option can only be used in /etc/fstab, and will be
ignored when part of the Options= setting in a unit file.
See systemd-makefs@.service(8).
wipefs(8) may be used to remove any signatures from a block device
to force x-systemd.makefs to reinitialize the device.
Added in version 236.
x-systemd.growfs
The file system will be grown to occupy the full block device. If
the file system is already at maximum size, no action will be
performed. It is hence expected that this option remains set even
after the file system has been grown. Only certain file system types
are supported, see systemd-makefs@.service(8) for details.
Note that this option can only be used in /etc/fstab, and will be
ignored when part of the Options= setting in a unit file.
Added in version 236.
x-systemd.pcrfs
Measures file system identity information (mount point, type, label,
UUID, partition label, partition UUID) into PCR 15 after the file
system has been mounted. This ensures the systemd-pcrfs@.service(8)
or systemd-pcrfs-root.service services are pulled in by the mount
unit.
Note that this option can only be used in /etc/fstab, and will be
ignored when part of the Options= setting in a unit file. It is also
implied for the root and /usr/ partitions discovered by systemd-gpt-
auto-generator(8).
Added in version 253.
x-systemd.rw-only
If a mount operation fails to mount the file system read-write, it
normally tries mounting the file system read-only instead. This
option disables that behaviour, and causes the mount to fail
immediately instead. This option is translated into the
ReadWriteOnly= setting in a unit file.
Added in version 246.
_netdev
Normally the file system type is used to determine if a mount is a
"network mount", i.e. if it should only be started after the network
is available. Using this option overrides this detection and
specifies that the mount requires network.
Network mount units are ordered between remote-fs-pre.target and
remote-fs.target, instead of local-fs-pre.target and
local-fs.target. They also pull in network-online.target and are
ordered after it and network.target.
Added in version 235.
noauto, auto
With noauto, the mount unit will not be added as a dependency for
local-fs.target or remote-fs.target. This means that it will not be
mounted automatically during boot, unless it is pulled in by some
other unit. The auto option has the opposite meaning and is the
default.
Note that if x-systemd.automount (see above) is used, neither auto
nor noauto have any effect. The matching automount unit will be
added as a dependency to the appropriate target.
Added in version 215.
nofail
With nofail, this mount will be only wanted, not required, by
local-fs.target or remote-fs.target. Moreover, the mount unit is not
ordered before these target units. This means that the boot will
continue without waiting for the mount unit and regardless whether
the mount point can be mounted successfully.
Added in version 215.
x-initrd.mount
An additional filesystem to be mounted in the initrd. See
initrd-fs.target description in systemd.special(7). This is both an
indicator to the initrd to mount this partition early and an
indicator to the host to leave the partition mounted until final
shutdown. Or in other words, if this flag is set it is assumed the
mount shall be active during the entire regular runtime of the
system, i.e. established before the initrd transitions into the host
all the way until the host transitions to the final shutdown phase.
Added in version 215.
If a mount point is configured in both /etc/fstab and a unit file that
is stored below /usr/, the former will take precedence. If the unit file
is stored below /etc/, it will take precedence. This means: native unit
files take precedence over traditional configuration files, but this is
superseded by the rule that configuration in /etc/ will always take
precedence over configuration in /usr/.
OPTIONS
Mount unit files may include [Unit] and [Install] sections, which are
described in systemd.unit(5).
Mount unit files must include a [Mount] section, which carries
information about the file system mount points it supervises. A number
of options that may be used in this section are shared with other unit
types. These options are documented in systemd.exec(5), systemd.kill(5)
and systemd.resource-control(5). The options specific to the [Mount]
section of mount units are the following:
What=
Takes an absolute path or a fstab-style identifier of a device node,
file or other resource to mount. See mount(8) for details. If this
refers to a device node, a dependency on the respective device unit
is automatically created. (See systemd.device(5) for more
information.) This option is mandatory. Note that the usual
specifier expansion is applied to this setting, literal percent
characters should hence be written as "%%". If this mount is a bind
mount and the specified path does not exist yet it is created as
directory.
Where=
Takes an absolute path of a file or directory for the mount point;
in particular, the destination cannot be a symbolic link. If the
mount point does not exist at the time of mounting, it is created as
either a directory or a file. The former is the usual case; the
latter is done only if this mount is a bind mount and the source
(What=) is not a directory. This string must be reflected in the
unit filename. (See above.) This option is mandatory.
Type=
Takes a string for the file system type. See mount(8) for details.
This setting is optional.
If the type is "overlay", and "upperdir=" or "workdir=" are
specified as options and the directories do not exist, they will be
created.
Options=
Mount options to use when mounting. This takes a comma-separated
list of options. This setting is optional. Note that the usual
specifier expansion is applied to this setting, literal percent
characters should hence be written as "%%".
SloppyOptions=
Takes a boolean argument. If true, parsing of the options specified
in Options= is relaxed, and unknown mount options are tolerated.
This corresponds with mount(8)'s -s switch. Defaults to off.
Added in version 215.
LazyUnmount=
Takes a boolean argument. If true, detach the filesystem from the
filesystem hierarchy at time of the unmount operation, and clean up
all references to the filesystem as soon as they are not busy
anymore. This corresponds with umount(8)'s -l switch. Defaults to
off.
Added in version 232.
ReadWriteOnly=
Takes a boolean argument. If false, a mount point that shall be
mounted read-write but cannot be mounted so is retried to be mounted
read-only. If true the operation will fail immediately after the
read-write mount attempt did not succeed. This corresponds with
mount(8)'s -w switch. Defaults to off.
Added in version 246.
ForceUnmount=
Takes a boolean argument. If true, force an unmount (in case of an
unreachable NFS system). This corresponds with umount(8)'s -f
switch. Defaults to off.
Added in version 232.
DirectoryMode=
Directories of mount points (and any parent directories) are
automatically created if needed. This option specifies the file
system access mode used when creating these directories. Takes an
access mode in octal notation. Defaults to 0755.
TimeoutSec=
Configures the time to wait for the mount command to finish. If a
command does not exit within the configured time, the mount will be
considered failed and be shut down again. All commands still running
will be terminated forcibly via SIGTERM, and after another delay of
this time with SIGKILL. (See KillMode= in systemd.kill(5).) Takes a
unit-less value in seconds, or a time span value such as "5min 20s".
Pass 0 to disable the timeout logic. The default value is set from
DefaultTimeoutStartSec= option in systemd-system.conf(5).
Check systemd.unit(5), systemd.exec(5), and systemd.kill(5) for more
settings.
SEE ALSO
systemd(1), systemctl(1), systemd-system.conf(5), systemd.unit(5),
systemd.exec(5), systemd.kill(5), systemd.resource-control(5),
systemd.service(5), systemd.device(5), proc(5), mount(8), systemd-fstab-
generator(8), systemd.directives(7), systemd-mount(1)
NOTES
1. API File Systems
https://systemd.io/API_FILE_SYSTEMS
systemd 257.9 SYSTEMD.MOUNT(5)
Generated by dwww version 1.16 on Sat Dec 6 14:26:39 CET 2025.