mount(1M) DG/UX 5.4.2 mount(1M)
NAME
mount, umount - mount and dismount filesystems
SYNOPSIS
mount [ -p ]
mount -a [ fnv ] [ -t type ]
mount [ -fnrv ] [ -t type ] [ -o options ] filesystem directory
mount [ -vfn ] [ -o options ] filesystem | directory
umount [ -t type ] [ -h host ] [ -e ]
umount -a [ v ] [ -e ]
umount [ -v ] [ -e ] filesystem | directory ...
DESCRIPTION
Use mount to mount file systems, or to display currently mounted file
systems. Use umount to unmount file systems. Alternatively, you may
use the Mount and Unmount operations in the File_System->Local and
File_System->Remote menus of sysadm.
The mount command has four formats:
mount [ -p ] With no arguments, it displays currently
mounted file systems.
mount -a [ options ] With no arguments but with the a(ll) switch,
it mounts some or all of the file systems
listed in the file /etc/fstab.
mount [ options ] filesystem directory
With two arguments, it mounts the named
filesystem on the named directory.
mount [ options ] filesystem | directory
With one argument, it mounts the named
filesystem or directory, using a matching
command line in the file /etc/fstab.
The umount command has three formats:
umount [ -t type -h host ] [ -e ]
With no arguments, it unmounts file systems of
the specified type or from the specified host,
that are listed in the file /etc/mnttab
umount -a [ v ] [ -e ]
With no argument but with the a(ll) switch, it
unmounts the file systems listed in the file
/etc/mnttab.
umount [ -v ] [ -e ] filesystem | directory
With one argument, it unmounts the file system
that is mounted from filesystem, or mounted on
directory.
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Arguments
The filesystem argument names the file system to be mounted or
unmounted. It may be local or remote. To specify a local file system,
enter for filesystem a pathname that resolves to a local resource,
such as: a disk partition (a logical disk created with admldisk), a
tape or cdrom device, or an area of memory. To specify a remote (nfs)
file system, enter the filesystem argument as host:pathname, where
host is the remote host's name and pathname is a directory on the
remote host.
The directory argument is the mount point: the pathname of a
directory on the local system. The directory must already exist.
Usually, the mount point should be an empty directory: if not empty,
its contents are hidden while the filesystem is mounted on it.
If directory is a symbolic link, the filesystem is mounted on the
resolution directory rather than on the symbolic link.
Options
-p Display the mounted filesystems in a format suitable 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/mnttab entry, but do not actually mount any
filesystems.
-n Mount the filesystem without making an entry in
/etc/mnttab.
-v Verbose. Display a message indicating each filesystem
being mounted.
-t type Specify a filesystem type. The accepted types are dg/ux,
cdrom, dos, swap, and nfs. See options below for the
arguments relevant for each type; see fstab(4) for a more
detailed 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, magnetic tape, and cdrom
filesystems should be mounted read-only. If they are
mounted read-write, errors occur when the system attempts
to update access times, even if no write operation is
attempted.
-o options
Specify filesystem option arguments--one or more comma-
separated words from the list below. Some options are
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valid for all filesystem types, while others apply to a
specific type only.
These option arguments are valid for all filesystem types:
ro | rw Allow read-only or read-write access.
Note: cdrom file systems are mounted
read-only regardless of this argument.
nosuid Setuid execution disallowed.
noauto If this filesystem is currently mounted
read-only, do not mount it. If the
filesystem is not currently mounted,
display an error message.
The default for cdrom filesystems is ` ro,suid '. For all
other types, the default is ` rw,suid '.
These option arguments are valid for dg/ux filesystems:
fsynconclose
Whenever a file in this mounted file system
is closed, write its dirty pages to disk.
This option decreases the likelihood of data
loss in the event of a system crash, but may
degrade performance.
fscklogsize=n
Log changes to system data in a manner that
allows fast recovery by fsck. This option
may degrade performance.
ramdisk Mount a memory-resident file system. See
mfs(4) for a detailed description of memory-
resident file systems.
If the ramdisk argument is present, the following three
arguments are also allowed:
usewiredmemory
By default, the data in the memory file
system is subject to being swapped to disk.
Use this argument to prevent swapping.
maxfilespace=n
The default number of blocks in a memory file
system is 2048. Use this argument to set the
maximum size to n blocks. No memory is
allocated until it is actually used. If the
usewiredmemory argument is present, n may
exceed the available memory. If this happens,
the system allocates as many blocks as there
are available, up to n; it does not report an
error.
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maxfilecount=n
The default number of file nodes that can be
allocated in a memory file system is 16384.
Use this argument to set the maximum to n.
If the usewiredmemory argument is present,
n may cause available memory to be exceeded.
If this happens, the system allocates as many
file nodes as available memory allows, up to
n nodes; it does not report an error.
This option argument is only valid for cdrom filesystems:
noversion ISO-9660 CDs have file names that have a
version number at the end of the name. This
is to allow multiple versions of the same
file to exist in the same directory with the
same base name. To remove the version number
(usually a -1), specify this option. If
there are multiple files with the same base
name, then the first one found in the
directory will be the only one that is
accessible with basename. The other versions
can be specified by typing in the entire
name, including the version number.
These option arguments are valid for nfs (NFS) filesystems:
bg | fg If the first attempt fails, retry in the
background, or, in the foreground.
secure Requires clients to use a more secure
protocol when accessing the directory.
Secure RPC using DES Authentication is an
additional feature that must be purchased
separately from the DG/UX (Trademark) ONC
(Trademark)/NFS® product. You must have this
feature to use the secure option.
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.
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intr Allow keyboard interrupts to kill (or signal)
a process that is hung waiting for a response
from a remote server.
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 modification.
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/mnttab that are
remote-mounted from host.
-e With the -e flag set, the umount command does not wait for
remote servers to respond when unmounting nfs mounted
filesystems. This is useful when a system needs to be
shutdown in a hurry. The -e flag does not solve the
problem of long delays with nested hard mounts. A nested
mount is a remote mount on a mount point that is also a
remote mount point. The remote mount points may be on the
same or different machines. For example, on system A you
mount /foo from system B. Then on system A you mount /bar
from system C on the mount point /foo from system B making
/foo/bar. If system B is down when you attempt to umount
/bar on system C, an indefinite delay in your system
shutdown could occur. Using soft mounts is a solution for
read-only file systems. In general you must avoid nested
mounts to insure a timely shutdown.
-t type Unmount all filesystems listed in /etc/mnttab that are of a
given type.
-a Unmount all filesystems currently mounted (as listed in
/etc/mnttab).
-v Verbose. Display a message indicating each filesystem
being unmounted.
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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
retransmissions 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 to prevent possible loss of data; and the intr option to
enable keyboard interrupts.
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/usr /usr
To mount all DG/UX filesystems:
mount -at dg/ux
To mount a remote filesystem:
mount serv:/usr/src /usr/src
To mount a remote filesystem that is listed in /etc/fstab:
mount /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
To mount a memory file system (the name /dev/memtmp is arbitrary and
will be created by the mount command):
mount -o ramdisk /dev/memtmp /mnt
To mount a memory file system using wired memory:
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mount -o ramdisk,usewiredmemory /dev/memtmp2 /memory1
FILES
/etc/mnttab table of mounted filesystems
/etc/fstab table of filesystems mounted at boot
SEE ALSO
fsck(1M), mountd(1M), nfsd(1M), dgmount(2), mkdir(2), open(2),
umount(2), fstab(4), fs(4), mfs(4), mnttab(4),
/usr/include/sys/dgmount.h, /usr/include/sys/nfs.h.
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