MOUNT_UFS(8) Maintenance Commands and Procedures MOUNT_UFS(8)

NAME

mount_ufs - mount ufs file systems

SYNOPSIS

mount -F ufs [generic_options] [-o specific_options]
[-O] special | mount_point


mount -F ufs [generic_options] [-o specific_options]
[-O] special mount_point

DESCRIPTION

The mount utility attaches a ufs file system to the file system
hierarchy at the mount_point, which is the pathname of a directory.
If mount_point has any contents prior to the mount operation, these
are hidden until the file system is unmounted.


The ufs file system supports direct mounting of files containing the
file system as well as block devices. See mount(8) and lofiadm(8).


If mount is invoked with special or mount_point as the only
arguments, mount will search /etc/vfstab to fill in the missing
arguments, including the specific_options. See mount(8).


If special and mount_point are specified without any
specific_options, the default is rw.


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 on top of the symbolic link
itself.

OPTIONS

See mount(8) for the list of supported generic_options.


The following options are supported:

-o specific_options

Specify ufs file system specific options in a comma-separated
list with no intervening spaces. If invalid options are
specified, a warning message is printed and the invalid options
are ignored. The following options are available:

dfratime | nodfratime

By default, writing access time updates to the disk may be
deferred (dfratime) for the file system until the disk is
accessed for a reason other than updating access times.
nodfratime disables this behavior.

If power management is enabled on the system, do not set
nodfratime unless noatime is also set. If you set nodfratime
without setting noatime, the disk is spun up every time a
file within a file system on the disk is accessed - even if
the file is not modified.


forcedirectio | noforcedirectio

If forcedirectio is specified and supported by the file
system, then for the duration of the mount, forced direct I/O
will be used. If the filesystem is mounted using
forcedirectio, data is transferred directly between user
address space and the disk. If the filesystem is mounted
using noforcedirectio, data is buffered in kernel address
space when data is transferred between user address space and
the disk. forcedirectio is a performance option that is of
benefit only in large sequential data transfers. The default
behavior is noforcedirectio.


global | noglobal

If global is specified and supported on the file system, and
the system in question is part of a cluster, the file system
will be globally visible on all nodes of the cluster. If
noglobal is specified, the mount will not be globally
visible. The default behavior is noglobal.


intr | nointr

Allow (do not allow) keyboard interrupts to kill a process
that is waiting for an operation on a locked file system. The
default is intr.


largefiles | nolargefiles

If nolargefiles is specified and supported by the file
system, then for the duration of the mount it is guaranteed
that all regular files in the file system have a size that
will fit in the smallest object of type off_t supported by
the system performing the mount. The mount will fail if there
are any files in the file system not meeting this criterion.
If largefiles is specified, there is no such guarantee. The
default behavior is largefiles.

If nolargefiles is specified, mount will fail for ufs if the
file system to be mounted has contained a large file (a file
whose size is greater than or equal to 2 Gbyte) since the
last invocation of fsck on the file system. The large file
need not be present in the file system at the time of the
mount for the mount to fail; it could have been created
previously and destroyed. Invoking fsck (see fsck_ufs(8)) on
the file system will reset the file system state if no large
files are present. After invoking fsck, a successful mount of
the file system with nolargefiles specified indicates the
absence of large files in the file system; an unsuccessful
mount attempt indicates the presence of at least one large
file.


logging | nologging

If logging is specified, then logging is enabled for the
duration of the mounted file system. Logging is the process
of storing transactions (changes that make up a complete UFS
operation) in a log before the transactions are applied to
the file system. Once a transaction is stored, the
transaction can be applied to the file system later. This
prevents file systems from becoming inconsistent, therefore
reducing the possibility that fsck might run. And, if fsck
is bypassed, logging generally reduces the time required to
reboot a system.

The default behavior is logging for all UFS file systems.

The log is allocated from free blocks in the file system, and
is sized approximately 1 Mbyte per 1 Gbyte of file system, up
to a maximum of 256 Mbytes. The log size may be larger (up to
a maximum of 512 Mbytes) dependent upon the number of
cylinder groups present in the file system.

Logging is enabled on any UFS file system, including root
(/), except under the following conditions:

o When logging is specifically disabled.

o If there is insufficient file system space for the
log. In this case, the following message is
displayed and file system is still mounted:

# mount /dev/dsk/c0t4d0s0 /mnt
/mnt: No space left on device
Could not enable logging for /mnt on /dev/dsk/c0t4d0s0.


The log created by UFS logging is continually flushed as it
fills up. The log is totally flushed when the file system is
unmounted or as a result of the lockfs -f command.


m

Mount the file system without making an entry in /etc/mnttab.


noatime

By default, the file system is mounted with normal access
time (atime) recording. If noatime is specified, the file
system will ignore access time updates on files, except when
they coincide with updates to the ctime or mtime. See
stat(2). This option reduces disk activity on file systems
where access times are unimportant (for example, a Usenet
news spool).

noatime turns off access time recording regardless of
dfratime or nodfratime.

The POSIX standard requires that access times be marked on
files. -noatime ignores them unless the file is also
modified.


nosec

By default, Access Control Lists (ACLs) are supported on a
mounted UFS file system. Use this option to disallow the
setting or any modification of an ACL on a file within a
mounted UFS file system. See getfacl(1) for background on
ACLs.


onerror = action

This option specifies the action that UFS should take to
recover from an internal inconsistency on a file system.
Specify action as panic, lock, or umount. These values cause
a forced system shutdown, a file system lock to be applied to
the file system, or the file system to be forcibly unmounted,
respectively. The default is panic.


quota

Quotas are turned on for the file system.


remount

Remounts a file system with a new set of options. All options
not explicitly set with remount revert to their default
values.


rq

Read-write with quotas turned on. Equivalent to rw, quota.


xattr | noxattr

Allow or disallow the creation and manipulation of extended
attributes. The default is xattr. See fsattr(7) for a description
of extended attributes.


-O

Overlay mount. Allow the file system to be mounted over an
existing mount point, making the underlying file system
inaccessible. If a mount is attempted on a pre-existing mount
point without setting this flag, the mount will fail, producing
the error "device busy".

EXAMPLES

Example 1: Turning Off (and On) Logging

The following command turns off logging on an already mounted file
system. The subsequent command restores logging.


# mount -F ufs -o remount,nologging /export
# (absence of message indicates success)
# mount -F ufs -o remount,logging /export


In the preceding commands, the -F ufs option is not necessary.

FILES

/etc/mnttab

table of mounted file systems


/etc/vfstab

list of default parameters for each file system

SEE ALSO

getfacl(1), fcntl(2), mount(2), stat(2), mnttab(5), vfstab(5),
attributes(7), fsattr(7), largefile(7), fsck(8), fsck_ufs(8),
lofiadm(8), mount(8), mountall(8)

NOTES

Since the root (/) file system is mounted read-only by the kernel
during the boot process, only the remount option (and options that
can be used in conjunction with remount) affect the root (/) entry in
the /etc/vfstab file.

June 22, 2009 MOUNT_UFS(8)