TMF Planning and Configuration Guide (H06.05+)

Reconfiguring Audit Trails
HP NonStop TMF Planning and Configuration Guide—540136-002
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Partitioning the Database
There are two situations in which the use of auxiliary audit trails can provide tangible
benefits:
•
If you want to partition the database and set different audit characteristics for
different volumes.
•
If your database application generates a large amount of audit information and you
want to improve performance.
Partitioning the Database
Setting up several audit trails allows you to configure each audit trail differently,
according to the needs of different parts of your database.
For example, if you have a set of data volumes generating a large amount of audit
information because the database partitions are being reloaded online, and you do not
want to provide file recovery for them, you might want to segregate those volumes onto
an auxiliary audit trail for which no dumping is done. Doing so can substantially reduce
both operator activity and tape usage that would be unnecessary in this situation.
As another example, a product from an outside vendor might scan the audit trail at the
same time it is written for some data volumes, slowing the audit generation rate for the
audit trail. If these volumes are configured to audit to an auxiliary audit trail, the
scanning will not affect the audit generation rate of the other data volumes.
Improving the Performance of Large Database Applications
If you are designing an extremely large database application that will generate enough
audit information each second during peak activity to drive the disk process to its
maximum capacity, you should divide the audit-trail activity among the master audit
trail (MAT) and one or more auxiliary audit trails. Keep the number of auxiliary audit
trails to a minimum, however, because using too many audit trails can create other
performance problems.
If you believe your application environment might grow to the point where its audit
generation would degrade performance, you can initially establish a minimally
configured, auxiliary audit trail (one active-audit volume, two audit-trail files on the
volume, no data volumes) that can be brought into use when the demand for it arises.
This type of configuration is an expensive alternative because you cannot use the
reserved, auxiliary audit-trail disk for audited database files (you can use it for
nonaudited files, as an overflow-audit volume, or as a restore-audit volume). Such a
configuration might be a less expensive proposition, however, than bringing down TMF
when you need to add the auxiliary audit trail.