MOUNT(8) Maintenance Commands and Procedures MOUNT(8)

NAME

mount, umount - mount or unmount file systems and remote resources

SYNOPSIS

mount [-p | -v]


mount [-F FSType] [generic_options] [-o specific_options]
[-O] special | mount_point


mount [-F FSType] [generic_options] [-o specific_options]
[-O] special mount_point


mount -a [-F FSType] [-V] [current_options]
[-o specific_options] [mount_points...]


umount [-f] [-V] [-o specific_options] special | mount_point


umount -a [-f] [-V] [-o specific_options] [mount_points...]

DESCRIPTION

mount attaches a file system to the file system hierarchy at the
mount_point, which is the pathname of a directory. If mount_point has
any contents prior to the mount operation, these are hidden until the
file system is unmounted.

umount unmounts a currently mounted file system, which may be
specified either as a mount_point or as special, the device on which
the file system resides.

The table of currently mounted file systems can be found by examining
the mounted file system information file. This is provided by a file
system that is usually mounted on /etc/mnttab. The mounted file
system information is described in mnttab(5). Mounting a file system
adds an entry to the mount table; a umount removes an entry from the
table.

When invoked with both the special and mount_point arguments and the
-F option, mount validates all arguments except for special and
invokes the appropriate FSType-specific mount module. If invoked with
no arguments, mount lists all the mounted file systems recorded in
the mount table, /etc/mnttab. If invoked with a partial argument list
(with only one of special or mount_point, or with both special or
mount_point specified but not FSType), mount will search /etc/vfstab
for an entry that will supply the missing arguments. If no entry is
found, and the special argument starts with /, the default local file
system type specified in /etc/default/fs will be used. Otherwise the
default remote file system type will be used. The default remote file
system type is determined by the first entry in the /etc/dfs/fstypes
file. After filling in missing arguments, mount will invoke the
FSType-specific mount module.

For file system types that support it, a file can be mounted directly
as a file system by specifying the full path to the file as the
special argument. In such a case, the nosuid option is enforced. If
specific file system support for such loopback file mounts is not
present, you can still use lofiadm(8) to mount a file system image.
In this case, no special options are enforced.

Only a user with sufficient privilege (at least PRIV_SYS_MOUNT) can
mount or unmount file systems using mount and umount. However, any
user can use mount to list mounted file systems and resources.

OPTIONS

-F FSType

Used to specify the FSType on which to operate. The FSType must
be specified or must be determinable from /etc/vfstab, or by
consulting /etc/default/fs or /etc/dfs/fstypes.


-a [ mount_points... ]

Perform mount or umount operations in parallel, when possible.

If mount points are not specified, mount will mount all file
systems whose /etc/vfstab "mount at boot" field is yes. If mount
points are specified, then /etc/vfstab "mount at boot" field will
be ignored.

If mount points are specified, umount will only umount those
mount points. If none is specified, then umount will attempt to
unmount all file systems in /etc/mnttab, with the exception of
certain system required file systems: /, /usr, /var, /var/adm,
/var/run, /proc, /dev/fd and /tmp.


-f

Forcibly unmount a file system.

Without this option, umount does not allow a file system to be
unmounted if a file on the file system is busy. Using this option
can cause data loss for open files; programs which access files
after the file system has been unmounted will get an error (EIO).


-p

Print the list of mounted file systems in the /etc/vfstab format.
Must be the only option specified. See BUGS.


-v

Print the list of mounted file systems in verbose format. Must be
the only option specified.


-V

Echo the complete command line, but do not execute the command.
umount generates a command line by using the options and
arguments provided by the user and adding to them information
derived from /etc/mnttab. This option should be used to verify
and validate the command line.


generic_options

Options that are commonly supported by most FSType-specific
command modules. The following options are available:

-m

Mount the file system without making an entry in /etc/mnttab.


-g

Globally mount the file system. On a clustered system, this
globally mounts the file system on all nodes of the cluster.
On a non-clustered system this has no effect.


-o

Specify FSType-specific options in a comma separated (without
spaces) list of suboptions and keyword-attribute pairs for
interpretation by the FSType-specific module of the command.
(See mount_ufs(8).) When you use -o with a file system that
has an entry in /etc/vfstab, any mount options entered for
that file system in /etc/vfstab are ignored.

The following options are supported:

devices | nodevices

Allow or disallow the opening of device-special files.
The default is devices.

If you use nosuid in conjunction with devices, the
behavior is equivalent to that of nosuid.


exec | noexec

Allow or disallow executing programs in the file system.
Allow or disallow mmap(2) with PROT_EXEC for files within
the file system. The default is exec.


loop

Ignored for compatibility.


nbmand | nonbmand

Allow or disallow non-blocking mandatory locking
semantics on this file system. Non-blocking mandatory
locking is disallowed by default.

If the file system is mounted with the nbmand option,
then applications can use the fcntl(2) interface to place
non-blocking mandatory locks on files and the system
enforces those semantics. If you enable this option, it
can cause standards conformant applications to see
unexpected errors.

To avoid the possibility of obtaining mandatory locks on
system files, do not use the nbmand option with the
following file systems:

/
/usr
/etc
/var
/proc
/dev
/devices
/system/contract
/system/object
/etc/mnttab
/etc/dfs/sharetab


Do not use the remount option to change the nbmand
disposition of the file system. The nbmand option is
mutually exclusive of the global option. See -g.


ro | rw

Specify read-only or read-write. The default is rw.


setuid | nosetuid

Allow or disallow setuid or setgid execution. The default
is setuid.

If you specify setuid in conjunction with nosuid, the
behavior is the same as nosuid.

nosuid is equivalent to nosetuid and nodevices. When suid
or nosuid is combined with setuid or nosetuid and devices
or nodevices, the most restrictive options take effect.

This option is highly recommended whenever the file
system is shared by way of NFS with the root= option.
Without it, NFS clients could add setuid programs to the
server or create devices that could open security holes.


suid | nosuid

Allow or disallow setuid or setgid execution. The default
is suid. This option also allows or disallows opening any
device-special entries that appear within the filesystem.

nosuid is equivalent to nosetuid and nodevices. When suid
or nosuid is combined with setuid or nosetuid and devices
or nodevices, the most restrictive options take effect.

This option is highly recommended whenever the file
system is shared using NFS with the root=option, because,
without it, NFS clients could add setuid programs to the
server, or create devices that could open security holes.


-O

Overlay mount. Allow the file system to be mounted over an
existing mount point, making the underlying file system
inaccessible. If a mount is attempted on a pre-existing mount
point without setting this flag, the mount will fail,
producing the error "device busy".


-r

Mount the file system read-only.

EXAMPLES

Example 1: Mounting and Unmounting a DVD Image Directly

The following commands mount and unmount a DVD image.


# mount -F hsfs /images/solaris.iso /mnt/solaris-image
# umount /mnt/solaris-image

USAGE

See largefile(7) for the description of the behavior of mount and
umount when encountering files greater than or equal to 2 Gbyte (
2^31 bytes).

FILES

/etc/mnttab

Table of mounted file systems.


/etc/default/fs

Default local file system type. Default values can be set for the
following flags in /etc/default/fs. For example: LOCAL=ufs

LOCAL:

The default partition for a command if no FSType is
specified.


/etc/vfstab

List of default parameters for each file system.

SEE ALSO

lofiadm(8), mount_hsfs(8), mount_nfs(8), mount_pcfs(8), fcntl(2),
mmap(2), lofs(4FS), pcfs(4FS), mnttab(5), vfstab(5), attributes(7),
largefile(7), privileges(7), mount_smbfs(8), mount_tmpfs(8),
mount_udfs(8), mount_ufs(8), mountall(8), umountall(8)

NOTES

If the directory on which a file system is to be mounted is a
symbolic link, the file system is mounted on the directory to which
the symbolic link refers, rather than on top of the symbolic link
itself.

September 8, 2015 MOUNT(8)