Technical data

Managing Storage Media
9.13 Using Mount Verification for Recovery
%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss.cc> %%%%%%%%%%%
Device <device-name> is offline.
Mount verification in progress.
When a device goes off line or is write-locked, mount verification sends two
messages:
• One message goes to OPCOM.
• The other message, distinguished by the prefix %SYSTEM-I-MOUNTVER,
goes directly to the system console (OPA0:), bypassing OPCOM.
The second message is a form of insurance in cases in which OPCOM is
unavailable. For example, if the system disk undergoes mount verification or
if OPCOM is not present on a system, you at least receive the messages with
the %SYSTEM-I-MOUNTVER prefix. Under normal circumstances, the operator
terminal receives both messages, with the %SYSTEM-I-MOUNTVER message
arriving first.
These messages notify you of the problem, and allow you to correct the problem
and recover the operation. When a pending mount verification is canceled by
timing out, OPCOM prints a message in the following format:
%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss.cc> %%%%%%%%%%%
Mount verification aborted for device <device-name>.
After a mount verification times out, all pending and future I/O requests to the
volume fail. You must dismount and remount the disk before users can access it
again.
Note
Mount verification caused by a write-lock error does not time out.
Mount Verification and Write-Locking
Suppose, for example, that a volume is mounted on a drive with write-lock off,
and someone toggles the WRITE LOCK switch. If mount verification is enabled
for the volume, the volume enters mount verification, and all I/O operations
to the volume are suspended until you recover the operation, as explained in
Section 9.13.2.4.
At mount time, if the system detects that the caches were not written back
the last time the volume was used, the system automatically rebuilds the file
information by scanning the contents of the volume. However, files being written
at the time of the improper dismount might be partially or entirely lost. See
Section 9.12 for details about analyzing and repairing these problems.
With the mount verification feature of disk and tape handling, users are generally
unaware that a mounted disk or tape has gone off line and returned on line, or in
some other way has become unreachable and then restored.
9.13.2 Using Mount Verification
The following sections explain how to perform these tasks:
Task Section
Enable and disable mount verification Section 9.13.2.1
9–74 Managing Storage Media