mount_cachefs(1M)					  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 information regarding back file systems,  refer
       to the System Administration Guide: Basic Administration.

       mount_cachefs  cannot  be  used	with replicated NFS mounts. mount_cachefs creates a pass through when used with an NFS version 4 mount. No
       caching is performed.

OPTIONS

       To mount a CacheFS file system, use the generic mount command 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  infor-
	       mation 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 permissions. 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.

	   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

ATTRIBUTES

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

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

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.

SunOS 5.10							    18 Mar 2004 						 mount_cachefs(1M)