TMF Planning and Configuration Guide (H06.05+)

Reconfiguring Audit Trails
HP NonStop TMF Planning and Configuration Guide—540136-002
3-9
Changing the Begin-Transaction-Disable Threshold
Decreasing the overflow threshold means that the audit trail will fill to a lower level
before TMF copies the earliest audit-trail file to an overflow-audit volume. If you set the
overflow threshold too low, the use of overflow-audit volumes could become
unacceptably high. TMF performance can be adversely affected when an excessive
number of files are copied from active-audit volumes to overflow-audit volumes.
Changing the Begin-Transaction-Disable
Threshold
The begin-transaction-disable threshold specifies, as a percentage of overall audit-trail
capacity, the point at which TMF prevents any new transactions from starting. The
default begin-transaction-disable threshold is 90%.
You can change the begin-transaction-disable threshold while transaction processing is
in progress by using the BEGINTRANSDISABLE parameter of the ALTER
AUDITTRAIL command.
Increasing the begin-transaction-disable threshold means that the audit trail fills to a
higher level before TMF prevents new transactions from starting. If you set the begin-
transaction-disable threshold too high, audited activity could cease until space
becomes available on the audit-trail volumes. In that situation, requests to data
volumes might be suspended, or data volumes might start going down, thus preventing
access to the audited database tables and files. Before increasing this threshold,
consider increasing the size of the audit trail.
Decreasing the begin-transaction-disable threshold means that the audit trail fills to a
lower level before TMF prevents new transactions from starting. If you set the begin-
transaction-disable threshold too low, new transactions could be disabled when there is
still enough space on the active or overflow-audit volumes for normal audit record
generation.
Note. You should configure enough space on the active-audit volumes to accommodate the
maximum anticipated transaction activity. Overflow-audit volumes are intended to relieve disk
space pressure under exceptional circumstances.
Caution. Do not change the begin-transaction-disable threshold unless you have detailed
records about audit record generation that support the reasons for making the change.
Changing the begin-transaction-disable threshold improperly can cause transaction processing
to stop.