mount_ufs(1M)						  System Administration Commands					     mount_ufs(1M)

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.

       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(1M).

       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 sym-
       bolic link refers, rather than on top of the symbolic link itself.

OPTIONS

       See mount(1M) 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  set-
	       ting  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 modi-
	       fied.

	   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 behav-
	       ior 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(1M)) 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  unsuc-
	       cessful 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 incon-
	       sistent, 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 64 Mbytes.

	       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.

	   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.

       -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".

       The  mount_ufs command supports the xattr flag, to allow the creation and manipulation of extended attributes. See fsattr(5) for a descrip-
       tion of extended attributes. The xattr flag is always on.

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

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       fsck(1M), fsck_ufs(1M), mount(1M), mountall(1M), fcntl(2), mount(2), stat(2), mnttab(4), vfstab(4), attributes(5), fsattr(5), largefile(5)

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.

SunOS 5.10							    27 Aug 2004 						     mount_ufs(1M)