NAME

mount, umount − mount and dismount file system

SYNOPSIS

/etc/mount [ fsname directory [ −frv ] [ −o options ] [ −t type ] ]
/etc/mount -a [ −fv ] [ −t type ]
/etc/mount -p

/etc/umount [ −v ] fsname
/etc/umount [ −v ] directory
/etc/umount -a [ −v ] [ −h host ] [ −t type ]

DESCRIPTION

The mount command announces to the system that a removable file system is to be attached to the file tree at directory. The directory must exist already; it becomes the name of the root of the newly mounted file system.  Directory must be given as an absolute path name.  Fsname must be either the name of a special file or of the form host:path. If fsname is of the form host:path, the file system type is assumed to be nfs.  (See −t option below.) 

These commands maintain a table of mounted devices in /etc/mnttab.  If invoked with no arguments, mount prints the table. 

The umount command announces to the system that the removable file system fsname previously mounted on directory directory is to be unmounted.  Either the file system name or the directory where the file system is mounted may be specified. 

Options (mount)

−a Attempt to mount all file systems described in /etc/checklist.  All optional fields in /etc/checklist must be included and supported.  If type is specified, all file systems in /etc/checklist with that type are mounted.  File systems are not necessarily mounted in the order listed in /etc/checklist. 

−f Force the file system to be mounted even if the file system clean flag indicates that the file system should have fsck(1M) run on it before mounting.

−p Print the list of mounted file systems in a format suitable for use in /etc/checklist. 

−r Mount the specified file system as read only.  This option implies −o ro.  Physically write-protected file systems must be mounted in this way or errors will occur when access times are updated, whether or not any explicit write is attempted. 

−t type Specify a file system type. The accepted types are hfs and nfs ; see checklist(4). If −a is not used, the single file system specified is mounted as that type.

−v Verbose mode.  Write a message to the standard output indicating which file system is being mounted. 

−o options Specify a list of comma-separated options from the list below.  Some options are valid for any file system type, while others apply to a specific type only. 

The following options are valid on all file systems:

defaultsUse all default options.  When used, this must be the only option specified. 

rwRead-write (default). 

roRead-only. 

suidSet-user-ID execution allowed (default). 

nosuidSet-user-ID execution not allowed. 

Options (umount)

−a Unmount all files described in /etc/mnttab. 

−h host
Unmount only those file systems listed in /etc/mnttab that are remote-mounted from host.

−t type
Unmount only file systems mounted with the given type.

−v Verbose mode.  Write a message to the standard output indicating which file system is being unmounted. 

NETWORKING FEATURES

NFS

The following options are specific to nfs file systems:

bgIf the first mount attempt fails, retry in the background. 

fgRetry in foreground (default). 

retry=nSet number of mount failure retries to n (default = 1). 

rsize=nSet read buffer size to n bytes (default set by kernel). 

wsize=nSet write buffer size to n bytes (default set by kernel). 

timeo=nSet NFS timeout to n tenths of a second (default = 7). 

retrans=nSet number of NFS retransmissions to n (default = 4). 

port=nSet server IP port number to n (default is the port customarily used for NFS servers). 

softReturn error if server does not respond. 

hardRetry request until server responds (default). 

intrPermit interrupts for hard mounts (default). 

nointrIgnore interrupts for hard mounts. 

The bg option causes mount to run in the background if the server’s mount daemon does not respond.  Mount attempts each request retry=n times before giving up.  Once the file system 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 file system returns an error on the request and a hard mounted file system retries the request.  By default, the retry requests for a hard mounted file system can be interrupted.  If the nointr option is specified, retry requests for a hard mounted file system will not be interruptable.  The retry requests will continue until successful.  File systems that are mounted rw (read-write) should use the hard option.  The number of bytes in a read or write request can be set with the rsize and wsize options. 

DIAGNOSTICS

Attempts to mount a currently mounted non-nfs volume under another name will result in an error. 

Umount complains if the special file is not mounted or if it is busy.  The file system is busy if it contains an open file or some user’s working directory. 

EXAMPLES

mount /dev/dsk/c0d0s4 /usr Mount a local disk. 

WARNINGS

Some degree of validation is done on the file system; however it is generally unwise to mount garbage file systems. 

DEPENDENCIES

Series 300 Diskless
Only NFS file systems can be mounted and unmounted from diskless nodes.

NFS

EXAMPLES

mount −t nfs serv:/usr/src /usr/src
Mount remote file system.

mount serv:/usr/src /usr/src
Same as above.

mount −o soft,ro serv:/usr/src /usr/src
Same as above but with a soft mount; the file system is mounted read-only.

AUTHOR

Mount was developed by HP, AT&T, the University of California, Berkeley, and Sun Microsystems. 

FILES

SEE ALSO

fsclean(1M), mount(2), mnttab(4), checklist(4). 

Hewlett-Packard Company  —  May 11, 2021