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 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].

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 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.

       •   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.

       •   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.

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. 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.

       x-systemd.makefs
           The file system or swap structure will be intialized 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 initalized.

           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.

       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.

       _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.

       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 the noauto option has an effect on the mount unit itself
           only — if x-systemd.automount is used (see above), then the matching automount unit
           will still be pulled in by these targets.

       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.

OPTIONS

       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 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. 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.

SEE ALSO

       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)

NOTES

        1. API File Systems
           https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems