TMF Planning and Configuration Guide (H06.05+)

Reconfiguring Audit Trails
HP NonStop TMF Planning and Configuration Guide—540136-002
3-6
Increasing Audit-Trail Capacity
The total recommended number of restore-audit volumes depends on their size. You
should configure enough restore-audit volume space to restore all the files you may
need to restore; if you are unsure, err on the side of too much space. Configuring
restore-audit volumes costs nothing; no restore volume space is allocated until it is
needed, and meanwhile the space can be used for other purposes.
Deleting a restore-audit volume decreases the space available for restored audit
dumps. If you delete a restore-audit volume that is currently in use by a recovery
procedure, the restore-audit volume remains in service until the restored dumps are no
longer needed. No further restored audit dumps are written to this volume after it is
successfully deleted from the audit-trail configuration.
Increasing Audit-Trail Capacity
As your business grows, your applications process more and more transactions. This
causes a corresponding increase in the amount of space used on the active-audit
volume, and an increase in the use of overflow-audit volumes.
If TMF must copy files from an active-audit volume on one disk drive to an overflow-
audit volume on another disk drive too often, TMF performance could be noticeably
affected. If transactions generate a large enough amount of audit information that the
available overflow space is consistently exceeded, your application risks reaching the
begin-transaction-disable threshold, which further degrades performance.
System administrators should regularly monitor audit-trail capacity. If you detect that
the audit trail is consistently exceeding the overflow threshold, you should issue an
ALTER AUDITTRAIL command, while transaction processing is in progress, to do any
of the following:
•
Increase the number of audit-trail files on the active-audit volume.
•
Add another active-audit volume.
•
Change the audit-trail file size. However, changing the audit-trail file size is more
disruptive than either of the above alternatives, and should be used only when
long-term planning suggests the need to increase the file size.
If there is more room on the active-audit volume, increase the number of files per
active-audit volume. If the active-audit volume is fully allocated, add another active-
audit volume.
Note that when you add an active-audit volume, the audit-trail capacity is increased by
the current configured number of files per active-audit volume.
TMF automatically aborts (backs out) transactions based on master audit-trail capacity.
If 45% of the total MAT capacity is consumed during a transaction, that transaction is
aborted.
Note. Before changing the number of files per active-audit volume or adding active-audit
volumes, make sure that the overflow threshold is not set too low, as described in Changing the
Overflow Threshold on page 3-8.