TMF Planning and Configuration Guide (H06.05+)

HP NonStop TMF Planning and Configuration Guide—540136-002
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Fallback Considerations
If you do not use any new configurable features after migrating to TMF 3.3, falling back
to the release from which you migrated is not a problem. If you use a new TMF 3.3
feature, however, it is important to first understand how that impacts any subsequent
fallback.
Adding Auxilliary Audit Trails While Started
If you add one or more auxilliary audit trails while TMF is started, it is only possible to
fall back to G06.24 or a later release version update (RVU). This is because the TMF
audit reading facilities prior to G06.24 cannot handle auxilliary pointer (AUXPTR)
records that specify a variable number of audit trails (the number of audit trails is, once
configured, assumed to remain constant).
If you issue an ADD AUDITTRAIL AUXnn command while TMF 3.3 is started, the next
AUXPTR record generated contains information for a different number of audit trails
than did the preceding AUXPTR record. In the G06.24 RVU, the audit reading module
can handle such AUXPTR records.
Format 2 Audit Trails
With respect to audit-trail format, the ability to fall back to an RVU that only supports
format 1 audit-trail files is analogous to the old RVU’s (whatever RVU you migrated
from) ability to read and comprehend the new format 2 audit-trail files. The new format
2 files have some new versions of audit records since RBA fields had to be extended
to INT(64) in those records. If you migrated to an RVU that supports format 2 audit-trail
files, but are still using format 1 audit-trail files, there are no issues with fallback
because the old RVU can interpret the format 1 audit-trail files.
After you use the TMFCOM command to transition to format 2 files, however, then
fallback may not be possible without a DELETE TMF because the old RVU cannot
read the new format 2 audit-trail files. If fallback is essential, you should attempt to get
the database in the best possible state. If fallback can be scheduled, you might be able
to transition back out of format 2 into format 1 files prior to falling back. However, once
you go to format 2 at all, to fall back without a DELETE TMF is complicated. The topics
that follow describe the time line for migration and transition to format 2, and the
fallback plan appropriate given the situation.