TMF Reference Manual (G06.24+)

TMFCOM Commands
HP NonStop TMF Reference Manual—522418-002
3-58
ALTER AUDITTRAIL
MAXRETAINEDATFILES does not guarantee that an audit-trail file will be restored
from tape only once. Space requirements and the impact of other recoveries all play a
part in determining which audit-trails files are retained indefinitely.
The current MAXRETAINEDATFILES value remains in effect until you explicitly change
it by entering a new value or using RESET MAXRETAINEDATFILES, or until you
request a DELETE TMF operation:
•
If you enter an ALTER AUDITTRAIL command without the
MAXRETAINEDATFILES option, the current MAXRETAINEDATFILES value is
unchanged.
•
If you never enter an ALTER AUDITTRAIL command with the
MAXRETAINEDATFILES option, or if you enter this command with RESET
MAXRETAINEDATFILES specified, the MAXRETAINEDATFILES attribute is set to
its default value of 0.
If you specify RESET MAXRETAINEDATFILES, any retained audit-trail files presently
on disk are purged immediately after they are no longer needed.
Other Operational Considerations
The FILESIZE attribute, whose initial value is assigned with the ADD AUDITTRAIL
command, cannot be changed with the ALTER AUDITTRAIL command. To alter this
value, you must purge the existing TMF configuration with the DELETE TMF command
and then create an entirely new configuration.
When you specify the ALTER AUDITTRAIL command with DELETEACTIVEVOL for an
active-audit volume or DELETEOVERFLOWVOL for an overflow volume, and that
Note. You cannot use the ADD AUDITTRAIL command to set the MAXRETAINEDATFILES
value; the MAXRETAINEDATFILES option is only available with ALTER AUDITTRAIL.
Each time TMF is started, all audit-trail files on restore-audit volumes are purged automatically.
Thus, any subsequent recovery is always forced to restore any needed audit trails that were
dumped to tape.
Caution. Before you decrease the size of the audit trail, determine whether such a change
might interrupt transaction processing. TMF does not alert you to the possibility that the audit
trail could exceed its BEGINTRANSDISABLE threshold when you issue an ALTER
AUDITTRAIL command to decrease the files per active volume or delete an active volume
from the configuration.
If the audit trail exceeds its BEGINTRANSDISABLE threshold, new transactions cannot start.
In this case, transaction processing is suspended until audit trail capacity drops below the
threshold.
If the OVERFLOW threshold is exceeded as a result of reduced audit trail capacity, the first
pinned audit-trail file is copied to the overflow volume.
Be careful not to lower the BEGINTRANSDISABLE or OVERFLOW threshold below your TMF
system’s current capacity levels; they will engage precisely in accordance with your request.