TMF Planning and Configuration Guide (H06.05+)

Reconfiguring Audit Trails
HP NonStop TMF Planning and Configuration Guide—540136-002
3-7
Increasing Audit-Trail Throughput
The 45% value cannot be changed in the configuration. If this feature causes TMF to
abort transactions that should not be aborted, you must increase the audit-trail capacity
by either increasing the number of audit-trail files per volume or by adding another
active-audit volume. When the additional audit-trail space is no longer needed, you
can reduce the audit trail to its original size.
In addition, TMF has an autoabort threshold based on a configurable transaction
timeout value.
If any audit-trail sequence number is 900,000 or more, TMF must be stopped and re-
configured with larger audit-trail sizes in the near future. TMF will stop abruptly, and
cannot be restarted, at the rollover of the audit trail (master of auxilliary) after the
999,999th audit trail is filled.
Increasing Audit-Trail Throughput
There are two situations in which disk head contention could arise and affect TMF
performance:
1. During audit dumping, if there is only one active-audit volume
2. During file recovery, if a restore-audit volume and active-audit volume are
configured on the same physical disk drive
For the first type of contention, you can either manually defer audit dumping to a later
time with a DISABLE AUDITDUMP command (as described in Pausing and Resuming
Audit Dumping on page 5-9) or add another active volume with an ADD AUDITTRAIL
command. As explained earlier under Number of Active-Audit Volumes on page 3-4,
multiple active-audit volumes are used in alternating sequence for greater efficiency.
For the second type of contention, you can use an ALTER AUDITTRAIL command to
move the restore-audit volume to a disk drive other than the one containing the active-
audit volume.
Moving Active-Audit Volumes
Assume that you originally configured the master audit trail with one active-audit
volume on the disk drive $TM01, and now you want to move the audit trail from $TM01
to the disk drive $TM02. You could do so by using ALTER AUDITTRAIL commands to
first add $TM02 as a new active-audit volume for the MAT, and then delete $TM01 as
an active-audit volume.
$TM02 becomes the active-audit volume, and $TM01 is marked as “deleting” (it
remains in the deleting state until all of the audit-trail files on it have been dumped).
Although marked as deleting, $TM01 can immediately be used for other purposes—for
example, as a data volume.