1    /ABORT

    Requires volume ownership or the user privilege VOLPRO (volume
    protection) to use this qualifier with a volume that was mounted
    with neither the /GROUP nor the /SYSTEM qualifier. Additionally
    requires the user privilege SHARE if the volume is mounted
    privately by a process other than the process issuing the
    DISMOUNT command.

    Specifies that the volume is to be dismounted, regardless of who
    mounted it. The primary purpose of the /ABORT qualifier is to
    terminate mount verification. The DISMOUNT/ABORT command also
    cancels any outstanding I/O requests. If the volume was mounted
    with the /SHARE qualifier, the /ABORT qualifier causes the volume
    to be dismounted for all of the users who mounted it.

2    /CLUSTER

    Dismounts a volume throughout a mixed-architecture OpenVMS
    Cluster system. If you specify DISMOUNT/CLUSTER, the DISMOUNT
    command checks for open files or other conditions that will
    prevent a Files-11 volume on the local node from dismounting.
    If the DISMOUNT command does not find any open files or other
    conditions, it checks for conditions on all other nodes in
    the OpenVMS Cluster. If the DISMOUNT command finds one of the
    conditions on any node, it displays an error message identifying
    the device and the nodes on which the error occurred, followed by
    an error message indicating open files or other conditions on the
    volume.

    After the DISMOUNT command successfully dismounts the volume on
    the local node, it dismounts the volume on every other node in
    the existing OpenVMS Cluster environment. If the system is not a
    member of a cluster, the /CLUSTER qualifier has no effect.

3    /FORCE_REMOVAL

       /FORCE_REMOVAL ddcu:

    Expels a named shadow set member from the shadow set.

    If connectivity to a device has been lost and the shadow set
    is in mount verification, you can use the /FORCE_REMOVAL ddcu:
    to immediately expel a named shadow set member (ddcu:) from
    the shadow set. If you omit this qualifier, the device is not
    dismounted until mount verification completes.

    Note that you cannot use this qualifier in conjunction with the
    /POLICY=MINICOPY (=OPTIONAL) qualifier.

    The device specified must be a member of a shadow set that is
    mounted on the node where the command is issued.

4    /OVERRIDE

       /OVERRIDE=CHECKS

    Marks a Files-11 volume for dismounting even if files are open
    on the volume. If you specify DISMOUNT/OVERRIDE=CHECKS, the
    DISMOUNT command displays messages indicating any open files or
    other conditions that prevent dismounting, immediately followed
    by a message indicating that the volume has been marked for
    dismounting.

    This command does not close open files on the device. A device
    cannot be properly dismounted until either all processes with
    open files have properly closed them, or the processes have been
    rundown completely.

    A substantial amount of time can pass between the time you enter
    the DISMOUNT/OVERRIDE=CHECKS command and the completion of the
    dismount operation. Always wait for the dismount to complete
    before you remove the volume. (To verify that the dismount
    has completed, enter the SHOW DEVICES command.) Note that the
    final phase of volume dismounting occurs in the file system, and
    all open files on the volume must be closed before the actual
    dismount can be done. Note also that the file system cannot
    dismount a volume while any known file lists associated with
    it contain entries.

    By using this command, the device is marked for dismount. This
    prevents additional processes from opening files on the device
    while existing open files are closed.

5    /POLICY

       /POLICY=[NO]MINICOPY[=(OPTIONAL)] (Alpha/Integrity servers
       only)

    Controls the setup and use of the shadowing minicopy function.

    Requires LOG_IO (logical I/O) privilege to create bitmaps.

    The exact meaning of the MINICOPY keyword depends on the context
    of the DISMOUNT command, as follows:

    1. If this is a dismount of a single member from a multi-member
       shadow set, a write bitmap is created to track all writes
       to the shadow set. This write bitmap may be used at a later
       time to return the removed member to the shadow set with a
       minicopy.

       If the write bitmap cannot be initiated and the keyword
       OPTIONAL is not specified, the dismount will fail and the
       member will not be removed.

       If you omit the /POLICY qualifier or if you specify
       /POLICY=NOMINICOPY, no bitmap will be created.

    2. If this is the final dismount of the shadow set in the
       cluster, the shadow set is verified to be capable of a future
       minicopy operation.

       If the shadow set has only one member or is in a merge state,
       and if OPTIONAL was not specified, the dismount will fail.

       Specifying neither NOMINICOPY nor MINICOPY is the same as
       MINICOPY=OPTIONAL, as the set will be dismounted regardless of
       the prior checks.

    For additional information, see the VSI Volume Shadowing for
    OpenVMS.

6    /UNIT

    Dismounts only one volume of a volume set on the specified
    device. By default, all volumes in a set are dismounted.

                                   NOTE

       Avoid dismounting the root volume of a volume set, because
       it contains the master file directory (MFD). It may be
       impossible to access files on a volume set if the MFD is
       not accessible.

7    /UNLOAD

       /UNLOAD
       /NOUNLOAD

    Determines whether the device on which the volume is mounted is
    physically unloaded. If you specify the DISMOUNT command without
    the /UNLOAD or the /NOUNLOAD qualifier, the qualifier that you
    specified with the MOUNT command (either /UNLOAD or /NOUNLOAD)
    determines whether the volume is unloaded physically.