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 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.
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)] (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.
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.