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)