MOUNT(8)MOUNT(8)NAME
mount, umount - mount and dismount filesystems
SYNOPSIS
/usr/etc/mount [ -p ]
/usr/etc/mount -a [ vd [ f | n ]] [ -t type ]
/usr/etc/mount [ -rvd [ f | n ]] [ -t type ] [ -o options ] fsname dir
/usr/etc/mount [ -vd [ f | n ]] [ -o options ] fsname | dir
/usr/etc/umount [ -t type ] [ -h host ]
/usr/etc/umount -a[v]
/usr/etc/umount [ -v ] fsname | dir
DESCRIPTION
The mount command attaches a filesystem fsname to the file tree at the
directory dir. The directory dir may or may not already exist. If dir
already exists, its contents are hidden until the filesystem is
unmounted, and dir becomes the name of the newly mounted root. If
fsname is of the form host:path the filesystem type is assumed to be
nfs.
The umount command detaches the filesystem fsname previously mounted on
directory dir. Either the filesystem name or the mounted-on directory
may be used.
The mount and umount commands maintain a table of mounted filesystems
in /etc/mtab, described in mtab(5). The mount command mounts entries
onto the filesystem from data it finds in one of two places. If
NetInfo is running, it comes from netinfo(5). Otherwise, the entries
are stored in /etc/fstab(5). Note that boot time mounts of type "4.3"
filesystems always occur before NetInfo is running, and so must be
stored in /etc/fstab to be seen by the system. If invoked without an
argument, mount displays the table from /etc/mtab. If invoked with
only one of fsname or dir mount searches the filesystem table for an
entry whose dir or fsname field matches the given argument. For
example, if this line is in /etc/fstab:
/dev/sd1a /usr 4.3 rw 1 1
then the commands mount /usr and mount /dev/sd1a are short for mount
/dev/sd1a /usr
MOUNT OPTIONS-p Print the list of mounted filesystems in a format suitable for
use in /etc/fstab.
-a Attempt to mount all the filesystems described in the filesystem
table. (In this case, fsname and dir are taken from the
filesystem table.) If a type is specified all of the
filesystems in the filesystem table with that type are mounted.
Filesystems are not necessarily mounted in the order listed in
the table.
-f Fake a new /etc/mtab entry, but do not actually mount any
filesystems.
-n Mount the filesystems without updating /etc/mtab. (This can be
useful for recovering from an overly full disk.)
-v Verbose — mount displays a message indicating the filesystem
being mounted.
-d Don't check if NFS mount appears to be mounting a directory on
top of itself. Otherwise, mount ignores such requests. Since
the NFS daemon on a machine might not have the same filesystem
root as the mount process, this option may be necessary in a
chroot'ed environment.
-t The next argument is the filesystem type. The accepted types
are 4.3, nfs, dos, macintosh, and cfs (CD-ROM file system). See
fstab(5) for a description of these filesystem types.
-r Mount the specified filesystem read-only. This is short for:
mount -o ro fsname dir
Physically write-protected and magnetic tape filesystems must be
mounted read-only, or errors occur when access times are updated
whether or not any explicit write is attempted.
-o Specify options, a 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.
The following is a list of options valid on all file systems
(the default is rw,suid if the filesystem is mounted by root and
rw,nosuid if the filesystem is not mounted by root):
rw read/write.
ro read-only.
suid set-uid execution allowed (cannot be specified; default
if root mounts the filesystem).
nosuid set-uid execution not allowed.
noauto do not mount this file system automatically (mount -a).
remount
change the mount options on this file system without
unmounting it first.
options specific to nfs (NFS) file systems. The defaults are:
fg,mnttimeo=20,retry=1,timeo=7,retrans=3,port=NFS_PORT,hard
The defaults for rsize and wsize set by the kernel.
bg if the first mount attempt fails, retry in the
background.
fg retry in foreground.
mnttimeo=n
set mount timeout to n seconds.
retry=n
set number times to retry mount to n.
rsize=n
set read buffer size to n bytes.
wsize=n
set write buffer size to n bytes.
timeo=n
set NFS timeout to n tenths of a second.
retrans=n
set number of NFS retransmissions to n.
port=n set server IP port number to n.
soft return error if server doesn't respond. Do not use this
option with the rw option.
hard retry request until server responds.
intr allow keyboard interrupts on hard mounts.
net Tell the NFS automounter to recognize this as a "network"
mount. The mount command will ignore these entries and
allow the autonfsmount(8) to take care of them. This
option allows one to create a uniform view of the network
from all machines. Typically, the mount point specified
is "/Net". A mount of the form "mount -o net
MACHINE:PATH /Net" translates to "mount MACHINE:PATH
/Net/MACHINE/PATH". If the mount is performed on the
machine serving the file system, then no actual mount
occurs. Instead, a symbolic link is created from
"/Net/MACHINE" to "/".
acregmin=n
set minimum time interval (in seconds) for file entry
caching
acregmax=n
set maximum time interval (in seconds) for file entry
caching
acdirmin=n
set minimum time interval for directory entry caching
acdirmax=n
set maximum time interval for directory entry caching
noac set no file attribute caching
The bg option causes mount to run in the background if the
server's mountd(8) does not respond. mount attempts each
request retry=n times before giving up. 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 retrans=n retransmissions have been sent with no reply a
soft mounted filesystem returns an error on the request and a
hard mounted filesystem prints a message and retries the
request. Filesystems that are mounted rw (read-write) should
use the hard option. The intr option allows keyboard interrupts
to kill a process that is hung waiting for a response on a hard
mounted filesystem. The number of bytes in a read or write
request can be set with the rsize and wsize options.
The attribute caching options can be used to defeat or modify client-
side caching of attributes relating to objects accessed via NFS from a
server. Changing these options can have a severe impact on the client-
side performance of an NFS filesystem. A typical scenario where
changing the parameters is beneficial is a multi-workstation
development environment, where multiple clients are performing
read/write file access to a common source file set.
UMOUNT OPTIONS-h host
Unmount all filesystems listed in /etc/mtab that are remote-
mounted from host.
-a Attempt to unmount all the filesystems currently mounted (listed
in /etc/mtab). In this case, fsname is taken from /etc/mtab.
-v Verbose — umount displays a message indicating the filesystem
being unmounted.
EXAMPLES
mount /dev/sd1a /usr mount a local disk
mount -ft 4.3 /dev/nd0 / fake an entry for nd root
mount -at 4.3 mount all 4.3 filesystems
mount -t nfs serv:/usr/src /usr/src mount remote filesystem
mount serv:/usr/src /usr/src same as above
mount -o hard serv:/usr/src /usr/src same as above but hard mount
mount -p > /etc/fstab save current mount state
FILES
/etc/mtab table of mounted filesystems
/etc/fstab table of filesystems mounted at boot
SEE ALSOmount(2), unmount(2), fstab(5), mountd(8C), nfsd(8C), netinfo(5)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.
October 8, 1990 MOUNT(8)