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Index for Section 8 |
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Alphabetical listing for M |
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mount(8)
NAME
mount, umount - Mounts and dismounts file systems
SYNOPSIS
/usr/sbin/mount [-d] [-r|-u|-w] [-o option, ...] [-t [no]type] file-system
directory
/usr/sbin/mount [-el] [-t [no]type]
/usr/sbin/mount -a [-fv] [-t [no]type]
/usr/sbin/mount [-d] [-r|-u|-w] [-o option, ...] [-t [no]type] file-system
| directory
/usr/sbin/umount -a|-A -b [-fv] [-t type] [-h host]
/usr/sbin/umount [-fv] file-system ... | directory ...
PARAMETERS
file-system
Specifies one or more file systems. How you specify a file system
depends on whether it is UFS or NFS or AdvFS.
To specify a UFS, enter the name of its block device special file. For
example: /dev/rz3c. The mount command returns an error if you try to
mount file system on a partition that is already in use.
To specify a NFS, specify the host and path name in either of these
formats: host:path or path@host.
To specify an AdvFS fileset, enter the name of the file domain, a
pound-sign(#) character, and the name of the fileset. For example:
root_domain#root.
directory
Specifies one or more directories. The directory must exist before you
use the mount command. When the command is successful, the directory
becomes the name of the newly mounted root directory, its mount point.
FLAGS
There are flags for the mount command and for the umount commands.
Flags for mount:
-a Attempts to mount all the file systems described in the /etc/fstab
file. In this case, file-system and directory are taken from the
/etc/fstab file. If -t type is specified, all of the file systems in
the /etc/fstab file with that type will be mounted. Alternatively, if
type is prefixed with no, all the file systems in the /etc/fstab file
that do not have that type will be mounted. File systems are not
necessarily mounted in the order listed in the /etc/fstab file.
Note that it is possible to create and mount a file system on a device
that is currently part of an LVM logical volume. This is because
physical disks on which the Logical Volume Manager (LVM) creates
logical volumes are not protected from access by other programs. (Note
that LVM is no longer supported on Digital UNIX systems. See the
vollvmencap(8) reference page for information on migrating LVM volumes
to the Logical Storage Manager (LSM).)
-d Mounts a UNIX File System (UFS) even if it has not been unmounted
cleanly or checked by fsck for consistency. Also used to mount a CD-
ROM UFS file system.
Although you can employ the -d option to mount an AdvFS fileset,
Digital recommends that you do not. When an AdvFS fileset is mounted
with the -d option, AdvFS subsequently skips domain recovery (which
could cause data corruption).
-e Lists all mount points. Normally, mount does not list mount points
served by the automount daemon.
-f Performs a ``fake'' mount and does not actually mount the file system.
This flag is used to verify the arguments you plan to use with the
mount command.
-l Displays the value of all the file system options.
-o option[, option ...]
Specifies a list of comma-separated options. Every option specified is
used. Some options are valid for all file system types, while others
apply only to a specific type. See the mount -o Flag Options section
that is specific to your file system type for a description of the
options supported by that file system.
-r Mounts the specified file system with read-only access. This flag is
the equivalent of the following command:
mount -o ro file-system directory
Physically write-protected and magnetic tape file systems must be
mounted with read-only access or errors will occur when access times
are updated, whether or not any explicit write is attempted. Note that
-r and -w are paired; the default is -w.
-t [no]type
Specifies the file system type. The supported file systems are as
follows:
advfs - Advanced File System (AdvFS)
ufs - UNIX File System (UFS)
nfs - Network File System (NFS)
mfs - Memory file system (See mfs(8).)
cdfs - CD-ROM (Compact Disc Read Only Memory) File System (See cdfs(4).
This file system is often used on CD-ROMs that contain system
firmware.)
dvdfs - DVD-ROM (Digital Versatile Disk, Read-only) File System (See
dvdfs(4). This file system enables reading disks that are formated in
the Universal Disk Format (UDF).
See fstab(4) for a description of file system types. If the no prefix
is used, all file types except the one specified are mounted.
-u Requests that the system remount a file system so that it can update
any incore data blocks for ufs and AdvFS type file systems. This flag
works only for ufs and AdvFS file systems that are currently mounted
read-only and updates the file systems from read-only to read-write.
For example, the mount -u / command updates the root file system from
read-only to read-write.
-v Displays a message indicating which file system is being mounted
(verbose).
-w Mounts the specified file system with read/write access. This flag is
equivalent to the -o rw flag. Read/write is the default access.
Flags for umount:
-A Attempts to unmount all the file systems currently mounted.
-a Attempts to unmount all the file systems listed in the /etc/fstab file.
-b Broadcasts a message to all server machines in the subnetwork to remove
the client host's name from their NFS mountdtab files.
-f Performs a fast unmount operation that causes remote file systems to be
unmounted without notifying the server. This option is supported only
by NFS file systems.
-h host
Unmounts all file systems listed in the /etc/fstab file that are
remotely mounted from host.
-a -t type
Unmounts all file systems listed in the /etc/fstab file that are of the
specified type. Note, the -a flag must be used together with the -t
flag.
-v Displays a message indicating the file system is being unmounted
(verbose).
mount -o Flag Options
There are many options for the -o flag; they are discussed in the following
paragraphs.
AdvFS Options
The following options are valid for the Advanced File System (AdvFS):
atimes
Flushes to disk file access time changes for reads of regular files.
[Default behavior when neither atimes or noatimes is specified.]
noatimes
Marks file access time changes made for reads of regular files in
memory, but does not flush them to disk until other file modifications
occur. This behavior does not comply with industry standards and is
used to reduce disk writes for applications with no dependencies on
file access times.
rw Allows read/write access.
ro Allows read-only access.
rq Allows read/write access.
dual
Enables an AdvFS fileset to be mounted as a domain volume even though
it has the same AdvFS domain ID as a fileset that is already mounted.
sync
Causes all writes to be written immediately to disk as well as to the
buffer cache.
UFS Option
The following option is valid only for UFS:
dirty
Allows a file system to be mounted even if it was not cleanly
unmounted.
UFS and NFS Options
The following options are valid for UFS and NFS:
dev Allows access to block and character-special devices.
nodev
Disallows access from the file system to either block or character-
special devices.
rw Allows read/write access.
ro Allows read-only access.
suid
Allows set-user-ID execution.
nosuid
Prohibits set-user-ID execution.
sync
Causes all writes to be written immediately to disk as well as to the
buffer cache.
nosync
Specifies that writes may return before data is written to disk.
exec
Allows binary execution.
noexec
Prohibits binary execution.
grpid
New files inherit the parent directory's group ID. This is the default
and matches BSD's semantics.
nogrpid
SVID III semantics applied. For example, if the parent directory's
mode bits include IS_GID, then the new file will inherit the parent's
group ID. If IS_GID is off, then it inherits the process group ID.
For UFS and NFS file systems, the file system option defaults are rw,suid,
and exec.
NFS-Specific Options
The following options are valid for NFS file systems:
bg Retries in the background, if the first mount attempt fails.
fg Retries in the foreground.
retry=n
Sets the number of mount failure retries to n.
rsize=n
Sets the read buffer size to n bytes.
wsize=n
Sets the write buffer size to n bytes.
timeo=n
Sets the initial NFS timeout period for UDP mounts to n tenths of a
second. NFS continually adjusts the timing as a function of network
response time.
maxtimo=n
Sets the maximum time value, in seconds, allowed between request
transmissions [UDP mounts only].
retrans=n
Sets the number of NFS retransmissions to n.
intr
Allows hard mounted file system operations to be interrupted.
nintr
Prevents hard mounted file system operations from being interrupted.
soft
Returns an error if the server does not respond.
hard
Retries the request until the server responds.
nfsv2
Normally, the mount command tries to use Version 3 of the NFS protocol.
If the server does not support Version 3, then the mount command
retries the mount using Version 2. Specifying -o nfsv2 forces the
mount command to use NFS Version 2. NFS Version 3 is an enhanced
version of the NFS protocol that provides 64 bit file access, as well
as features designed to improve performance and correctness.
Alternatively, you can use the vers=2 flag.
nfsv3
Tries to use Version 3 of the NFS protocol. If the server does not
support it, Version 2 is used. This is the default.
Alternatively, you can use the vers=3 flag.
proto=type
Specifies the network transport: udp or tcp.
Specify udp to use UDP as the network transport. This is supported by
all known NFS servers. UDP works best in local, fast, and reliable
environments. The mount will fail if the server does not support NFS
over UDP. proto=udp is the default.
Specify tcp to use TCP as the network transport. This is supported by
some vendors, but not all. TCP works better than UDP in high-loss,
congested networks, and is the only way to use NFS over the Internet.
The mount will fail if the server does not support NFS over TCP.
The -o tcp syntax is compatible with 4.4BSD syntax, while the proto=tcp
syntax is compatible with Solaris 2.4 syntax.
port=n
Set the server IP port number to the value of n. The default is to
query the portmap daemon on the server for the port number (which is
almost always 2049). This option is useful only when the server is not
running the portmap daemon or is running multiple NFS servers. Both of
these situations are very rare.
proplist
Allows the use of extended attributes (property list) including access
control lists (ACLs) on this filesystem. The NFS server exporting this
filesystem must be running the proplistd daemon. See the proplist(4),
acl(4), and proplistd(8) reference pages
vers=n
Specifies the version of the NFS protocol. You can specify either
Version 3 or Version 2.
Normally, the mount command tries to use Version 3 of the NFS protocol.
If the server does not support Version 3, then the mount command
retries the mount using Version 2. Specifying vers=2 forces the mount
command to use NFS Version 2. NFS Version 3 is an enhanced version of
the NFS protocol that provides 64 bit file access, as well as features
designed to improve performance and correctness.
Alternatively, you can use the nfsv2 or nfsv3 flag.
For NFS, the defaults are fg, retry=10000, timeo=11, retrans=4, hard, and
intr. Defaults for rsize and wsize are set by the kernel.
The bg option causes mount to run in the background if the server's mountd
does not respond. The mount command attempts each request retry times
before giving up. Once the file system is mounted, each NFS request made
in the kernel waits timeo tenths of a second for a response. If no
response arrives, the timeout period is multiplied by 2 and the request is
retransmitted.
When retrans 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. 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.
NFS Update Visibility Options
These options control how quickly you see updates to a file or directory
that has been modified by another host. Increasing these values gives you
slightly better performance. Decreasing the values decreases the time it
takes for you to see modifications made on the other host. If you are the
only person modifying files under this mount point, you should increase
these values.
acdirmin=n
Holds cached directory attributes for at least n seconds.
acdirmax=n
Holds cached directory attributes for no more than n seconds.
The maximum value you can specify is 3600.
acregmin=n
Holds cached file attributes for at least n seconds.
acregmax=n
Holds cached file attributes for no more than n seconds. The
maximum value you can specify is 3600.
actimeo=n Sets all four attributes' cache timeout values to n.
noac Does not set attribute caching. This option is equivalent to
actimeo=0.
nocto Does not get a fresh attribute when opening a file.
The NFS Update Visibility Option defaults are acdirmin=30, acdirmax=60,
acregmin=3, and acregmax=60.
CDFS Options
The following options are valid for the CD-ROM File System (CDFS):
defperm Ignores the permission bits, if present, and defaults all file
and directory permissions to the value 0555, with a zero User ID
(UID) (owned by root). Files and directories recorded on an ISO
9660-formatted file system might or might not have permission
bits. This setting is a default option since the permissions on
most existing ISO 9660-formatted CD-ROMs do not map to the UID
scheme that is used.
nodefperm Uses the on-disk permission bits, if present. If a file or
directory is not recorded with permission bits, the default 0555
is used.
noversion Strips off the extension (;#) from the version string if a file
recorded on an ISO 9660-formatted file system or a file system
formatted by the High Sierra Group contains a version string.
File and directory names are displayed in lowercase letters and
name matching is performed in a case-insensitive manner. Use
this option if you are mounting a CD-ROM containing MS-DOS
applications.
This option does not work correctly if file names contain
multibyte characters, such as those in the SJIS and BIG-5
codesets that are commonly used in Japan and Taiwan,
respectively. When file names contain multibyte characters, using
the noversion option is likely to corrupt the display of some
characters in the name.
rrip Uses the Rock Ridge Interchange Protocol (RRIP) extensions to ISO
9660 (if present on the file system) to provide mixed-case file
names, device special files, and other attributes for files on
the file system. If there are no RRIP extensions on the file
system, the file system will be mounted and the option will be
ignored.
The defaults for CDFS are ro, nodev, and defperm.
DESCRIPTION
Use the mount command to make a file system available for use, or mounted.
Use the umount command to make a file system unavailable for use, or
unmounted.
The format used in the mount command determines the format returned by
getfsstat and getmntinfo.
If the mount command is invoked with only a file-system or directory
specified, the command searches the /etc/fstab file for an entry whose
file-system or directory field matches the argument specified with the
command.
For example, if the line /dev/rz0g /usr ufs rw 1 1 is specified in the
/etc/fstab file, both of these two commands, mount /usr and mount /dev/rz0g
are equivalent to the following command:
# mount /dev/rz0g /usr
The umount command announces to the system that file system file-system
previously mounted on directory should be removed. Either the file system
name or the directory mount point can be specified in the command line.
To use the mount and unmount commands, you must be the root user. An
exception to this restriction is made when NFS file systems have been
explicitly exported to allow nonroot users to mount the file system. Refer
to the -n option of mountd(8) for more information.
The mount command also lets you mount an ISO 9660- or HSG-formatted file
system onto a directory.
No more than one user should mount a disk partition with read/write access
or the file system might become corrupted.
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 being mounted on top of the symbolic link itself.
When you boot to single-user mode, the root file system is mounted with
read-only access. If you want to modify a file, you must change the options
on the root file system to read/write. You can do this with the following
command:
# mount -u /
If your /etc/fstab file is corrupted, you can mount the root file system
with the following command:
# mount -u /dev/rz?? /
General users cannot mount UFS file systems. Mounting UFS file systems
requires superuser privilege. By default, the maximum number of UFS mounts
is 1,000. However, you can modify this value by using the sysconfig
command. For example:
# sysconfig -r vfs max-ufs-mounts=1100
The default for CDFS is not to allow access to device special files (option
nodev) since the device numbers recorded on a disc using RRIP extensions
might not match the device numbers used by the operating system. If you
wish to allow device access, mount the file system with the dev option and
use the cddevsuppl command to map the device numbers of the device special
files on the disc to new device numbers used by the operating system.
message The mount command attempts to dynamically load the cdfs kernel
modules if they are not statically built into the running kernel. However,
you must be the root user to dynamically load the cdfs kernel modules.
Other users receive the following error should they attempt the operation:
mount: super user priviliges required to load cdfs module
All other errors that could occur as the cdfs kernel modules are being
dynamically loader produce the following error message:
mount: Can't load cdfs module
Refer to cdfs(4) for information on the correct system configuration
options to set before using CDFS.
NFS mounts can fail due to authentication requirements on the server. For
example, a Client credential too weak message is returned if a normal user
attempts to mount and the server only allows root user mounting. A Server
rejected credential message is returned if the server is not able to
resolve the client's IP address.
If your workstation has multiple network interfaces, the server must be
able to resolve all IP addresses from which it might receive mount
requests. See the mountd(8) reference page or the Network Administration
manual for more information.
When you mount the first fileset in an AdvFS domain, AdvFS determines
whether or not it can access all data in all volumes of that domain. If
AdvFS determines that the size of any volume in the domain is actually
smaller than the size recorded for that volume in the domain's metadata,
there are two possible outcomes:
1. The mount succeeds, but in read-only mode. In this case, AdvFS is
able to read the last currently in-use block on the volume. A message
similar to the following is displayed:
Actual size of virtual disk /dev/vol/vol01 is 100352 blocks
but recorded size is 102400 blocks.
Mounting fileset staff#grads in read-only mode.
2. The mount fails. In this case, AdvFS cannot read the last currently
in-use block on the volume. A message similar to the following is
displayed:
Actual size of virtual disk /dev/vol/vol01 is 100352 blocks
but recorded size is 102400 blocks.
Cannot read essential data on /dev/vol/vol01.
Corrupted volume found; failing mount of staff#grads.
staff#grads on /grads: I/O error
When you attempt to mount an AdvFS fileset in an AdvFS domain, the number
of volumes pointed to by the /etc/fdmns/dmn_name links must equal the
number of volumes in the domain. If you attempt to mount an AdvFS file
system with an incorrect number of volumes, the following message will
appear on the console:
# Volume count mismatch for domain dmn_name.
dmn_name expects 2 volumes, /etc/fdmns/dmn_name has 1 links.
To correct the problem , you must match the number of volumes and then
mount them. See advscan(8) for more information.
RESTRICTIONS
The mount and umount commands support mount point argument pathnames of up
to MNAMELEN, which includes the null terminating character. MNAMELEN can
be up to 90 characters long, including the null terminating character.
ERRORS
The following warning messages are displayed only if you use the -v option.
· Warning: partition special-device and overlapping partition(s) are
marked in use in the disklabel.
The specified partition overlaps with another partition or partitions
that have the fstype field set.
· Warning: partition(s) which overlap special-device are marked in use
in the disklabel.
The partition overlaps another partition or partitions that have the
fstype field set.
· Warning: the disklabel for special-device does not exist or is
corrupted.
The device specified either does not have a disklabel or the disklabel
has been corrupted.
· Warning: unable to check special-device against active AdvFS domains
because the directory /etc/fdmns seems to be missing or wrong.
There was a failure when checking the overlap with AdvFS domains. The
failure is with /etc/fdmns or /etc/fdmns/dom, or and active domain
does not exist.
· Warning: unable to check special-device against active swap devices
because special swap files are missing.
A failure occurred when checking the overlap with active swap devices.
The special device files associated with active swap devices are
invalid.
· Warning: unknown overlap condition errno encountered for partition
special-device.
An unknown overlap condition was encountered for the specified device.
The following are fatal error messages.
· Error: an overlapping partition is open.
A partition that overlaps the specified partition is open.
· Error: special-device is an invalid device or cannot be opened.
The specified device is invalid and an overlapping partition is open.
· Error: special-device contains a fstype file system.
The specified partition and overlapping partitions have the fstype
field set.
· Error: Unknown severe error errno encountered for partition special-
device.
An unknown overlap condition was encountered for the specified device.
EXAMPLES
1. To mount a local disk, enter:
% mount /dev/rz0g /usr
2. To mount an AdvFS fileset, enter:
% mount -t advfs usr_dmn#user1 /usr/user1
or
% mount usr_dmn#user1 /usr/user1
3. To mount all ufs file systems, enter:
% mount -at ufs
4. To mount a remote file system, enter:
% mount -t nfs serv:/usr/src /usr/src
5. To mount a remote file system with a hard mount, enter:
% mount -o hard serv:/usr/src /usr/src
6. To mount an ISO 9660- or HSG-formatted file system from block device
/dev/rz3c onto the local directory /cdfs with the file version strings
stripped off, enter:
% mount -t cdfs -o noversion /dev/rz3c /cdfs
7. To mount a UFS CD-ROM (for example, the installation CD-ROM) from
block device /dev/rz3c onto the local directory cdrom, enter:
% mount -r /dev/rz3c /cdrom
FILES
/usr/sbin/mount
Specifies the command path.
/usr/sbin/umount
Specifies the command path.
/etc/fstab
Contains static information about file systems.
RELATED INFORMATION
Commands: mountd(8), mfs(8), nfsd(8), cddevsuppl(8), proplistd(8)
Functions: mount(2), mount(2sv), umount(2), umount(2sv), umount(3)
Files: advfs(4), cdfs(4), fstab(4), mountdtab(4), proplist(4), acl(4)