VMS Help DISMOUNT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Closes a mounted disk or tape volume for further processing and
    deletes the logical name associated with the device.

    Requires the GRPNAM (group logical name) and SYSNAM (system
    logical name) privileges to dismount group and system volumes.

    Format

      DISMOUNT  device-name[:]

1 - Parameter

 device-name[:]

    Name of the device containing the volume-either a logical name or
    a physical name. If a physical name is specified, the controller
    defaults to A and the unit defaults to 0.

    If the volume currently mounted on the device is a member of a
    disk or tape volume set, all volumes in the set are dismounted,
    unless the /UNIT qualifier is specified.

2 - Qualifiers

 2.1 - /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.

 2.2 - /CLUSTER

    Dismounts a volume throughout a dual-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.

 2.3 - /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.

 2.4 - /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.

 2.5 - /POLICY

       /POLICY=[NO]MINICOPY[=(OPTIONAL)]

    Controls the setup and use of the shadowing minicopy function.

    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, refer to Volume Shadowing for
    OpenVMS.

 2.6 - /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.

 2.7 - /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.

3 - Examples

    1.$ MOUNT MTA0: PAYVOL TAPE
         .
         .
         .
      $ DISMOUNT TAPE

      The MOUNT command in this example mounts the tape whose volume
      identification is PAYVOL on the device MTA0: and assigns the
      logical name TAPE to the device. By default, the volume is not
      shareable. The DISMOUNT command releases access to the volume,
      deallocates the device, and deletes the logical name TAPE.

    2.$ MOUNT/SHARE DKA3:  DOC_FILES
         .
         .
         .
      $ DISMOUNT DKA3:

      The MOUNT command in this example mounts the volume labeled
      DOC_FILES on the device DKA3. Other users can enter MOUNT
      commands to access the device. The DISMOUNT command shown in
      this example deaccesses the device for the process issuing the
      command. If other users still have access to the volume, the
      volume remains mounted for their process or processes.

    3.$ DISMOUNT/NOUNLOAD  DMA2:

      The DISMOUNT command in this example dismounts the volume; the
      /NOUNLOAD qualifier requests that the volume remain in a ready
      state.

    4.$ MOUNT/BIND=PAYROLL  DMA1:,DMA2:  PAYROLL01,PAYROLL02
         .
         .
         .
      $ DISMOUNT/UNIT  DMA2:

      The MOUNT command in this example mounts PAYROLL, a two-
      volume set. The DISMOUNT command dismounts only PAYROLL02,
      leaving PAYROLL01 accessible. Note that because the master file
      directory (MFD) for the volume set is on the root volume, you
      should not dismount the root volume (in this case, PAYROLL01)
      of the volume set.

    5.$ DISMOUNT $10$DJA100
      %DISM-W-CANNOTDMT, $10$DJA100: cannot be dismounted
      %DISM-W-INSWPGFIL, 4 swap or page files installed on volume
      %DISM-W-SPOOLEDEV, 3 devices spooled to volume
      %DISM-W-INSTIMAGE, 7 images installed on volume
      %DISM-W-USERFILES, 6 user files open on volume

      The DISMOUNT command in this example displays the open files
      and other conditions that prevent device $10$DJA100 from
      dismounting.

    6.$ DISMOUNT/CLUSTER $10$DJA100
      %DISM-W-RMTDMTFAIL, $10$DJA100: failed to dismount on node SALT
      %DISM-W-FILESOPEN, volume has files open on remote node
      %DISM-W-RMTDMTFAIL, $10$DJA100: failed to dismount on node PEPPER
      %DISM-W-FILESOPEN, volume has files open on remote node
      %DISM-W-CANNOTDMT, $10$DJA100: cannot be dismounted

      The DISMOUNT command in this example displays messages
      identifying device $10$DJA100 and nodes SALT and PEPPER on
      which errors occurred followed by messages indicating open
      files on the volume.