RDF/IMP and IMPX System Management Manual (RDF 1.3+)

Auxiliary Audit Trails
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
12-4
Usage of Master and Auxiliary Audit Trails
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When the primary system fails, an auxiliary extractor is running behind the master
extractor.
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A committed transaction (whose commit record was received by the master receiver
just before the primary system failure) updated only a volume associated with the
MAT.
RDF cannot know if a committed transaction touched only a data volume configured to
the MAT or if it also touched data volumes configured to one or more auxiliary audit
trails. In the above set of circumstances, therefore, RDF must regard the status of the
transaction as unknown. The updater for the MAT backs out the transaction and logs
pertinent information in its exception file. If this were to happen, your database
administrator might be able to use RDFSNOOP to examine the affected data pointed to
by the exception file. For information about using RDFSNOOP, refer to Appendix B,
Additional Reference Information.
Usage of Master and Auxiliary Audit Trails
A master extractor must always be associated with the MAT even if no data volumes are
configured to the MAT. A master extractor is required because the MAT contains audit
records that preserve TMF control information required by RDF on the backup system,
and this control information is not stored in any auxiliary audit trail.
Using Expand Multi-CPU Paths
The use of Expand with ATM or Fast Ethernet provides considerable bandwidth, and it
is often sufficient to have a single Expand path driven out of a single processor.
If your RDF configuration is replicating auxiliary audit trails, however, the total amount
of audit data to be sent from the primary system to the backup system could be more
than a single Expand path can handle. If that is the case, you should use the Expand
multi-CPU path feature.
Expand multi-CPU paths enable you to spread the communications load over multiple
processors by connecting multiple Expand line-handler processes, each in a separate
processor, between two adjacent nodes. In an RDF environment, you would use this
feature to establish dedicated paths for the master extractor-receiver pair and multiple
auxiliary extractor-receiver pairs.
Suppose you will be configuring three extractor-receiver pairs: one for the MAT and one
each for auxiliary audit trails AUX1 and AUX2. Suppose further that both your primary
and backup systems have ten processors. For each Expand multi-CPU path, you place
the matching Expand line-handlers in the same processor on both systems.
To set up our three paths in processors 3, 5, and 7, for example, you would put matching
Expand line-handlers in processor 3 on both systems, in processor 5 on both systems,
and in processor 7 on both systems. Within RDF you would then configure processor 3
as the primary CPU for the master extractor and receiver, processor 5 as the primary
CPU for the AUX1 extractor and receiver, and processor 7 as the primary CPU for the
AUX2 extractor and receiver. Thereafter all messages between the master extractor and
receiver will go through the path in processor 3 on both systems, all messages between