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Man page of mount
mount
Section: Maintenance Commands (8)
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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
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.
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:
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).)
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).
Lists all mount points. Normally, mount does not list mount points
served by the automount daemon.
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.
Displays the value of all the file system options.
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.
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.
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.
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.
Displays a message indicating which file system is being mounted (verbose).
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:
Attempts to unmount all the file systems currently mounted.
Attempts to unmount all the file systems listed in the /etc/fstab file.
Broadcasts a message to all server machines in the subnetwork to remove the
client host's name from their NFS mountdtab files.
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.
Unmounts all file systems listed in the /etc/fstab file that are
remotely mounted from host.
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.
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):
Flushes to disk file access time changes for reads of regular files.
[Default behavior when neither atimes or noatimes is
specified.]
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.
Allows read/write access.
Allows read-only access.
Allows read/write access.
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.
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:
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:
Allows access to block and character-special devices.
Disallows access from the file system to either block or character-special
devices.
Allows read/write access.
Allows read-only access.
Allows set-user-ID execution.
Prohibits set-user-ID execution.
Causes all writes to be written immediately to disk as well as to
the buffer cache.
Specifies that writes may return before data is written to disk.
Allows binary execution.
Prohibits binary execution.
New files inherit the parent directory's group ID. This is the default
and matches BSD's semantics.
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:
Retries in the background, if the first mount attempt fails.
Retries in the foreground.
Sets the number of mount failure retries to n.
Sets the read buffer size to n bytes.
Sets the write buffer size to n bytes.
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.
Sets the maximum time value, in seconds, allowed between
request transmissions [UDP mounts only].
Sets the number of NFS retransmissions to n.
Allows hard mounted file system operations to be interrupted.
Prevents hard mounted file system operations from being interrupted.
Returns an error if the server does not respond.
Retries the request until the server responds.
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.
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.
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.
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.
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
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.
Holds cached directory attributes for at least n seconds.
Holds cached directory attributes for no more than n seconds.
The maximum value you can specify is 3600.
Holds cached file attributes for at least n seconds.
Holds cached file attributes for no more than n seconds.
The maximum value you can specify is 3600.
Sets all four attributes' cache timeout values to n.
Does not set attribute caching. This option is equivalent to
actimeo=0.
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):
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.
Uses the on-disk permission bits, if present. If a file or directory is
not recorded with permission bits, the default 0555 is used.
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.
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:
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.
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
To mount a local disk, enter:
-
% mount /dev/rz0g /usr
To mount an AdvFS fileset, enter:
-
% mount -t advfs usr_dmn#user1 /usr/user1
or
-
% mount usr_dmn#user1 /usr/user1
To mount all ufs file systems, enter:
-
% mount -at ufs
To mount a remote file system, enter:
-
% mount -t nfs serv:/usr/src /usr/src
To mount a remote file system with a hard mount, enter:
-
% mount -o hard serv:/usr/src /usr/src
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
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
Specifies the command path.
Specifies the command path.
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)
delim off
Index
- NAME
-
- SYNOPSIS
-
- PARAMETERS
-
- FLAGS
-
- Flags for mount:
-
- Flags for umount:
-
- mount -o Flag Options
-
- AdvFS Options
-
- UFS Option
-
- UFS and NFS Options
-
- NFS-Specific Options
-
- NFS Update Visibility Options
-
- CDFS Options
-
- DESCRIPTION
-
- RESTRICTIONS
-
- ERRORS
-
- EXAMPLES
-
- FILES
-
- RELATED INFORMATION
-
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Time: 02:40:37 GMT, October 02, 2010