Technical data

Managing Storage Media
9.13 Using Mount Verification for Recovery
%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss.cc> %%%%%%%%%%%
Device <device-name> contains the wrong volume.
Mount verification in progress.
2. Once mount verification completes, the disk is marked as valid, and OPCOM
issues a message in the following format:
%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss.cc> %%%%%%%%%%%
Mount verification completed for device <device-name>.
3. I/O operations to the disk or tape proceed, as shown in the following example:
%%%%%%%%%%% OPCOM, 28-MAY-2000 11:54:54.12 %%%%%%%%%%%
Device DUA0: is offline.
Mount verification in progress.
%%%%%%%%%%% OPCOM, 28-MAY-2000 11:57:34.22 %%%%%%%%%%%
Mount verification completed for device DUA0:.
In this example, the message from OPCOM informs the operator that device
DUA0: went off line and mount verification was initiated. The operator finds
that the drive was accidentally powered down and successfully powers it up
again.
The last message in the example indicates that mount verification is satisfied
that the same volume is on the drive as before the error. All I/O operations to
the volume resume.
9.13.2.4 Recovering from Write-Lock Errors
Devices become write-locked when a hardware or user error occurs while a disk
or a tape volume is mounted for a write operation. For example, if a disk is write-
locked or a tape is missing a write ring, the hardware generates an error. As soon
as the software discovers that the disk or tape is write-locked (for example, when
an I/O operation fails with a write-lock error), mount verification begins.
OPCOM issues a message in the following format to the operators enabled for
DISKS and DEVICES or TAPES and DEVICES, announcing the unavailability of
the disk or tape:
%%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss.cc> %%%%%%%%%%%
Device <device-name> has been write-locked.
Mount verification in progress.
You can either recover the operation or terminate mount verification. Your
options include the following ones:
• Enable the drive for writing by toggling the hardware WRITE LOCK switch
of the disk, or check to see that a tape volume has a write ring.
• If the disk or tape drive is faulty, but another functioning drive is available on
the same controller, move the disk or tape to the functioning drive and swap
the unit select plugs. (Note that switching to another drive causes the volume
to undergo offline mount verification; once this completes, the write-lock
mount verification continues.)
• Terminate the mount operation by shutting down mount verification with one
of the techniques described in Section 9.13.2.5.
Once the mount verification software determines that the volume is in a
write-enabled state, I/O operations to the tape or disk resume with no further
messages.
9–76 Managing Storage Media