Optional.

    Dismounts one of the following:

    o  All file systems from all servers: DISMOUNT /ALL

    o  All file systems on the specified server: DISMOUNT /ALL
       /HOST=host

    o  All file systems on the specified device: DISMOUNT DNFSn: /ALL

    If you dismount using the /ALL qualifier, the dismount operation
    completes even if the server is not currently reachable.