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 .

       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 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 informa-
				  tion	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 con-
				  struct 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)

BUGS

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

SunOS 5.11							    18 Mar 2004 						 mount_cachefs(1M)