mount(1M) mount(1M)
NAME
mount, umount - mount and dismount filesystems
SYNOPSIS
/etc/mount [ -p ]
/etc/mount -a[fnv] [ -t type ]
/etc/mount [ -fnrv ] [ -t type ] [ -o options ] filesystem
directory
/etc/mount [ -fnrv ] [ -o options ] filesystem | directory
/etc/umount [ -t type ] [ -h host ]
/etc/umount -a[v]
/etc/umount [ -v ] filesystem | directory ...
DESCRIPTION
mount attaches a named filesystem to the filesystem hierar-
chy at the pathname location directory, which must already
exist. If directory has any contents prior to the mount
operation, these remain hidden until the filesystem is once
again unmounted. If filesystem is of the form
host:pathname, it is assumed to be an NFS filesystem (type
nfs).
umount unmounts a currently mounted filesystem, which can be
specified either as a directory or a filesystem.
mount and umount maintain a table of mounted filesystems in
/etc/mtab, described in mtab(4). If invoked without an
argument, mount displays the contents of this table. If
invoked with either a filesystem or directory only, mount
searches the file /etc/fstab for a matching entry, and
mounts the filesystem indicated in that entry on the indi-
cated directory.
MOUNT OPTIONS
-p Print the list of mounted filesystems in a format suit-
able for use in /etc/fstab.
-a All. Attempt to mount all the filesystems described in
/etc/fstab. If a type argument is specified with -t,
mount all filesystems of that type. Filesystems are
not necessarily mounted in the order shown in
/etc/fstab.
-f Fake an /etc/mtab entry, but do not actually mount any
filesystems.
-n Mount the filesystem without making an entry in
/etc/mtab.
-v Verbose. Display a message indicating each filesystem
being mounted.
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-t type
Specify a filesystem type. The accepted types are 4.2,
and nfs; see fstab(4) for a description of these types.
-r Mount the specified filesystem read-only, even if the
entry in /etc/fstab specifies that it is to be mounted
read-write.
Physically write-protected filesystems must be mounted
read-only. Otherwise errors occur when the system
attempts to update access times, even if no write
operation is attempted.
-o options
Specify filesystem options -list of comma-separated
words from the list below. Some options are valid for
all filesystem types, while others apply to a specific
type only.
options valid on all filesystems:
rw|ro Read/write or read-only.
suid|nosuid Setuid execution allowed or disal-
lowed.
grpid Create files with BSD semantics for
the propagation of the group ID.
Under this option, files inherit the
GID of the directory in which they
are created, regardless of the
directory's set-GID bit.
noauto Do not mount this filesystem that is
currently mounted read-only. If the
filesystem is not currently mounted,
an error results.
remount If the file system is currently
mounted, and if the entry in
/etc/fstab specifies that it is to
be mounted read-write or rw was
specified along with remount,
remount the file system making it
read-write. If the entry in
/etc/fstab specifies that it is to
be mounted read-only and rw was not
specified, the file system is not
remounted. If the file system is
not currently mounted, an error
results.
The default is `rw,suid'.
options specific to 4.2 filesystems:
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quota|noquota Usage limits are enforced, or are
not enforced. The default is
noquota.
options specific to nfs (NFS)filesystems:
bg|fg If the first attempt fails, retry in
the background, or, in the fore-
ground.
retry=n The number of times to retry the
mount operation.
rsize=n Set the read buffer size to n bytes.
wsize=n Set the write buffer size to n
bytes.
timeo=n Set the NFS timeout to n tenths of a
second.
retrans=n The number of NFS retransmissions.
port=n The server IP port number.
soft|hard Return an error if the server does
not respond, or continue the retry
request until the server responds.
intr Allow keyboard interrupts on hard
mounts.
secure Use a more secure protocol for NFS
transactions.
acregmin=n Hold cached attributes for at least
n seconds after file modification.
acregmax=n Hold cached attributes for no more
than n seconds after file modifica-
tion.
acdirmin=n Hold cached attributes for at least
n seconds after directory update.
acdirmax=n Hold cached attributes for no more
than n seconds after directory
update.
actimeo=n Set min and max times for regular
files and directories to n seconds.
Regular defaults are:
fg,retry=10000,timeo=7,retrans=3,port=NFSPORT,hard,\
acregmin=3,acregmax=60,acdirmin=30,acdirmax=60
Defaults for rsize and wsize are set internally by
the system kernel.
UMOUNT OPTIONS
-h host
Unmount all filesystems listed in /etc/mtab that are
remote-mounted from host.
-t type
Unmount all filesystems listed in /etc/mtab that are of
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a given type.
-a Unmount all filesystems currently mounted (as listed in
/etc/mtab).
-v Verbose. Display a message indicating each filesystem
being unmounted.
NFS FILESYSTEMS
Background vs. Foreground
Filesystems mounted with the bg option indicate that mount
is to retry in the background if the server's mount daemon
(mountd(1M)) does not respond. mount retries the request up
to the count specified in the retry=n option. Once the
filesystem is mounted, each NFS request made in the kernel
waits timeo=n tenths of a second for a response. If no
response arrives, the time-out is multiplied by 2 and the
request is retransmitted. When the number of retransmis-
sions has reached the number specified in the retrans=n
option, a filesystem mounted with the soft option returns an
error on the request; one mounted with the hard option
prints a warning message and continues to retry the request.
Read-Write vs. Read-Only
Filesystems that are mounted rw (read-write) should use the
hard option.
Interrupting Processes With Pending NFS Requests
The intr option allows keyboard interrupts to kill a process
that is hung while waiting for a response on a hard-mounted
filesystem.
Secure Filesystems
The secure option must be given if the server requires
secure mounting for the filesystem.
File Attributes
The attribute cache retains file attributes on the client.
Attributes for a file are assigned a time to be flushed. If
the file is modified before the flush time, then the flush
time is extended by the time since the last modification
(under the assumption that files that changed recently are
likely to change soon). There is a minimum and maximum
flush time extension for regular files and for directories.
Setting actimeo=n extends flush time by n seconds for both
regular files and directories.
EXAMPLES
To mount a local disk: mount /dev/dsk/0s2 /usr
To mount all 4.2 filesystems: mount -at 4.2
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To mount a remote filesystem: mount -t nfs
serv:/usr/src /usr/src
To mount a remote filesystem: mount serv:/usr/src
/usr/src
To hard mount a remote filesystem:
mount -o hard
serv:/usr/src /usr/src
To save current mount state: mount -p > /etc/fstab
FILES
/etc/mtab table of mounted filesystems
/etc/fstab table of filesystems mounted at boot
SEE ALSO
mount(2), unmount(2), umount(2) fstab(4), mtab(4),
mountd(1M), nfsd(1M)
BUGS
Mounting filesystems full of garbage crashes the system.
If the directory on which a filesystem is to be mounted is a
symbolic link, the filesystem is mounted on the directory to
which the symbolic link refers, rather than being mounted on
top of the symbolic link itself.
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