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.