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NAME | SYNOPSIS | DESCRIPTION | AUTOMATIC DEPENDENCIES | FSTAB | OPTIONS | SEE ALSO | NOTES | COLOPHON |
SYSTEMD.MOUNT(5) systemd.mount SYSTEMD.MOUNT(5)
systemd.mount - Mount unit configuration
mount.mount
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) binary 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 User= and
Group= options are not particularly useful for mount units specifying
a "Type=" option or using configuration not specified in /etc/fstab;
mount(8) will refuse options that are not listed in /etc/fstab if it
is not 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 additional
symlinks to it.
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].
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 BindsTo= and
After= type dependencies on the device unit encapsulating the block
device (see below).
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.
For mount units with DefaultDependencies=yes in the "[Unit]" section
(the default) a couple additional dependencies are added. Mount units
referring to local file systems automatically gain an After=
dependency on local-fs-pre.target. Network mount units automatically
acquire After= dependencies on remote-fs-pre.target, network.target
and network-online.target. Towards the latter a Wants= unit is added
as well. 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. Mount units (regardless if local or
network) also acquire automatic Before= and Conflicts= on
umount.target in order to be stopped during shutdown.
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).
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. See systemd-fstab-generator(8) for details about the
conversion.
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-timout=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.
x-systemd.before=, x-systemd.after=
Configures a Before= dependency or After= between the created
mount unit and 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.
x-systemd.requires-mounts-for=
Configures a RequiresMountsFor= 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= in systemd.unit(5) for details.
x-systemd.device-bound
The block device backed file system will be upgraded to BindsTo=
dependency. This option is only useful when mounting file systems
manually with mount(8) as the default dependency in this case is
Requires=. This option is already implied by entries in
/etc/fstab or by mount units.
x-systemd.automount
An automount unit will be created for the file system. See
systemd.automount(5) for details.
x-systemd.idle-timeout=
Configures the idle timeout of the automount unit. See
TimeoutIdleSec= in systemd.automount(5) for details.
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.
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.
noauto, auto
With noauto, this mount 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.
nofail
With nofail, this mount will be only wanted, not required, by
local-fs.target or remote-fs.target. This means that the boot
will continue even if this mount point is not mounted
successfully.
x-initrd.mount
An additional filesystem to be mounted in the initramfs. See
initrd-fs.target description in systemd.special(7).
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.
Mount 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) and systemd.kill(5).
The options specific to the [Mount] section of mount units are the
following:
What=
Takes an absolute path 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 "%%".
Where=
Takes an absolute path of a directory of the mount point. If the
mount point does not exist at the time of mounting, it is
created. 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.
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.
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.
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.
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 the manager configuration
file's DefaultTimeoutStartSec= variable.
Check systemd.exec(5) and systemd.kill(5) for more settings.
systemd(1), systemctl(1), 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)
1. API File Systems
https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2017-07-05. If you dis‐
cover any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
to man-pages@man7.org
systemd 234 SYSTEMD.MOUNT(5)
Pages that refer to this page: systemd(1), systemd-mount(1), systemd.automount(5), systemd.exec(5), systemd.kill(5), systemd.resource-control(5), systemd.swap(5), systemd.unit(5), systemd.directives(7), systemd.index(7), systemd-fstab-generator(8), systemd-gpt-auto-generator(8)