CFS(4)                                                     CFS(4)

     NAME
          cfs - cache file system

     SYNOPSIS
          cfs -s [-rd] [-f partition]

          cfs -a netaddr [-rd] [-f partition] [mtpt]

     DESCRIPTION
          Cfs is a user-level file server that caches information
          about remote files onto a local disk.  It is normally
          started by the kernel at boot time, though users may start
          it manually.  Cfs is interposed between the kernel and a
          network connection to a remote file server to improve the
          efficiency of access across slow network connections such as
          modem lines.  On each open of a file cfs checks the consis-
          tency of cached information and discards any old information
          for that file.

          Cfs mounts onto mtpt (default /) after connecting to the
          file server.

          The options are:

          s    the connection to the remote file server is on file
               descriptors 0 and 1.

          a netaddr
               dial the destination netaddr to connect to a remote
               file server.

          r    reformat the cache disk partition.

          d    turn on debugging

          f partition
               use file partition as the cache disk partition.

          All 9P messages except read, clone, and walk (see intro(5))
          are passed through cfs unchanged to the remote server.  A
          clone followed immediately by a walk is converted into a
          clwalk.  If possible, a read is satisfied by cached data.
          Otherwise, the file server is queried for any missing data.

     FILES
          /dev/hd0cache
               Default file used for storing cached data.

     SOURCE
          /sys/src/cmd/cfs

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