TMF Operations and Recovery Guide (G06.26+)

Recovery Methods
HP NonStop TMF Operations and Recovery Guide—522417-003
7-21
Recovering Audit-Trail Files Dumped to Disk
volume to free disk space for other files. When TMF is conducting multiple recovery
operations, recovery processes often must wait for TMF to copy the same audit-trail
files from tape repeatedly to support each recovery operation.
TMF allows you to override this standard restore-and-purge mechanism to keep the
restored audit-trail files on the restore-audit volume indefinitely. This option can
improve performance by:
•
Eliminating or minimizing the time a recovery process must wait for TMF to restore
an audit-trail file.
•
Minimizing disk contention for audit-trail files being read from, or restored to, the
same disk.
To use this option, issue the ALTER AUDITTRAILS command with the
MAXRETAINEDATFILES parameter specifying the number of audit-trail files you wish
to retain. For example, the following command retains up to the last 100 audit-trail files
on the restore-audit volumes, even after all recovery processes are complete:
TMF 65> ALTER AUDITTRAIL MAT, MAXRETAINEDATFILES 100
Use the MAXRETAINEDATFILES option when you expect to conduct many recovery
operations at or near the same time, keeping as many potentially required files on disk
as possible. When the recovery load diminishes, return to the standard restore-and-
purge mechanism for tape files by entering an ALTER AUDITTRAIL command with the
RESET MAXRETAINEDATFILES parameter, freeing disk space for other purposes.
For example:
TMF 70> ALTER AUDITTRAIL MAT, RESET MAXRETAINEDATFILES
Remember: MAXRETAINEDATFILES optimizes access time for files archived on tape;
RESET MAXRETAINEDATFILES maximizes available disk space.
Recovering Audit-Trail Files Dumped to Disk
For audit-trail files dumped to disk, TMF opens the disk dumps directly, rather than
copying them to a restore-audit volume. This operation is automatic for all recoveries
involving audit-trail dumps on disk. Because the restore time used for audit-trail dumps
on tape is entirely eliminated for dumps on disk, a recovery process never needs to
wait for audit-trail files to become available. (For this reason, the
MAXRETAINEDATFILES option in the ALTER AUDITTRAIL command does not apply
to dumps on disk.)
Recovery Scenarios
This section suggests actions you can take to prevent the most common problems that
occur on TMF systems. It also describes how to recover from these problems with
minimal interruption to system operations.