System Administration Commands			mount_cachefs(1M)


NAME
     mount_cachefs - mount CacheFS file	systems

SYNOPSIS
     mount	-F	 cachefs       [generic_options]       -o
     backfstype=file_system_type  [specific_options] [-O] special
     mount_point

DESCRIPTION
     The CacheFS-specific version of the mount command	mounts	a
     cached  file  system;  if	necessary, it NFS-mounts its back
     file system. It also provides a number  of	 CacheFS-specific
     options for controlling the caching process. For more infor-
     mation regarding back file	 systems,  refer  to  the  System
     Administration Guide: Basic Administration.

OPTIONS
     To	mount a	CacheFS	file system, use the generic  mount  com-
     mand with the  -F option followed by the argument cachefs.

     See mount(1M) for a list of supported generic_options.

     -o	specific_options
	   Specify CacheFS file	 system	 specific  options  in	a
	   comma-separated list	with no	intervening spaces.

	   acdirmax=n
		 Specifies that	cached attributes are held for no
		 more  than  n	seconds	 after	directory update.
		 After n seconds, all  directory  information  is
		 purged	 from  the cache. The default value is 30
		 seconds.

	   acdirmin=n
		 Specifies that	cached attributes are held for at
		 least	n seconds after	directory update. After	n
		 seconds, CacheFS checks to see	if the	directory
		 modification  time  on	 the back file system has
		 changed. If it	has, all  information  about  the
		 directory  is purged from the cache and new data
		 is retrieved from  the	 back  file  system.  The
		 default value is 30 seconds.

	   acregmax=n
		 Specifies that	cached attributes are held for no
		 more  than  n	seconds	 after file modification.
		 After n seconds, all file information is  purged
		 from the cache. The default value is 30 seconds.

	   acregmin=n
		 Specifies that	cached attributes are held for at
		 least n seconds after file modification. After	n
		 seconds, CacheFS  checks  to  see  if	the  file
		 modification  time  on	 the back file system has
		 changed. If it	has, all  information  about  the
		 file  is  purged  from	the cache and new data is
		 retrieved from	the back file system. The default
		 value is 30 seconds.

	   actimeo=n
		 Sets  acregmin, acregmax, acdirmin, and acdirmax
		 to n.

	   backfstype=file_system_type
		 The file system type of  the  back  file  system
		 (can be  nfs or hsfs).

	   backpath=path
		 Specifies where the back file system is  already
		 mounted.  If  this  argument  is  not	supplied,
		 CacheFS determines a mount point  for	the  back
		 file  system. The back	file system must be read-
		 only.

	   cachedir=directory
		 The name of the cache directory.

	   cacheid=ID
		 ID is a string	specifying a particular	 instance
		 of  a	cache.	If you do not specify a	cache ID,
		 CacheFS will construct	one.

	   demandconst
		 Verifies cache	consistency only when  explicitly
		 requested,  rather  than  the	periodic checking
		 that is done by default.  A consistency check is
		 requested   by	 using	the   -s  option  of  the
		 cfsadmin(1M) command.	This option is useful for
		 back  file systems that change	infrequently, for
		 example, /usr/openwin.	demandconst  and  noconst
		 are mutually exclusive.

	   local-access
		 Causes	the front file system  to  interpret  the
		 mode  bits  used  for access checking instead of
		 having	the back file system verify  access  per-
		 missions.  Do	not use	this argument with secure
		 NFS.

	   noconst
		 Disables cache	consistency checking. By default,
		 periodic   consistency	  checking   is	 enabled.
		 Specify noconst only when you know that the back
		 file  system  will  not  be  modified.	Trying to
		 perform cache consistency check  using	 cfsadmin
		 -s will result	in error. demandconst and noconst
		 are mutually exclusive.

	   ro |	rw
		 Read-only or read-write (default).

	   suid	| nosuid
		 Allow (default) or disallow  setuid execution.

	   write-around	| non-shared
		 Write modes for CacheFS. The  write-around  mode
		 (the  default)	 handles  writes  the same as NFS
		 does; that is,	writes are made	to the back  file
		 system, and the affected file is purged from the
		 cache.	You can	use the	non-shared mode	when  you
		 are sure that no one else will	be writing to the
		 cached	file system. In	this mode, all writes are
		 made to both the front	and the	back file system,
		 and the file remains in the cache.


     -O	   Overlay mount.  Allows the filesystem  to  be  mounted
	   over	 an  existing  mount point, making the underlying
	   filesystem inaccessible.  If	a mount	is attempted on	a
	   pre-existing	 mount	point  without setting this flag,
	   mount will fail with	the error:
	    mount -F cachefs: mount failed Device busy.

EXAMPLES
     Example 1:	CacheFS-mounting a File	System

     The  following  example  CacheFS-mounts  the   file   system
     server1:/user2,  which is already NFS-mounted on /usr/abc as
     /xyz.

     example# mount -F cachefs -o backfstype=nfs,backpath=/usr/abc,
	  cachedir=/cache1 server1:/user2 /xyz

     The lines similar to the following	appear in the /etc/mnttab
     file after	the mount command is executed:

     server1:/user2   /usr/abc	      nfs
     /usr/abc	      /cache1/xyz    cachefs	 backfstype=nfs

SEE ALSO
     cfsadmin(1M),  fsck_cachefs(1M),  mount(1M),   attributes(5)
     System Administration Guide: Basic	Administration

BUGS
     The output	for the	generic_option -p output is incorrect for
     cachefs.