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

Auxiliary Audit Trails
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
12-3
Configuring Updaters
Configuring Updaters
The SET VOLUME command includes the following optional syntax:
ATINDEX atindex
where atindex is an integer value from 0 through 15 specifying the audit trail to
which that data volume is mapped on the primary system. 0 specifies the MAT, and the
data volume on the primary system must be mapped to the MAT. 1 through 15 specifies
auxiliary audit trail AUX01 through AUX15, respectively, and the data volume on the
primary system must be mapped to the designated auxiliary audit trail.
The default value is 0.
Error Conditions
•
It is an error if the specified image trail atindex does not map to a receiver with
the same atindex.
•
It is an error if the updater’s atindex does not equal the same audit trail index to
which the data volume on the primary system is mapped.
•
It is an error if the atindex of the updater and its image trail are not the same.
STOP TMF Ramifications
Under normal circumstances, auxiliary extractors always run ahead of the master
extractor. Abnormal situations, such as CPU failures, can cause auxiliary extractors to
fall behind the master extractor.
If an auxiliary extractor is running behind the master extractor when you issue a STOP
TMF command, the TMF shutdown operation cannot complete until the auxiliary
extractor has caught up with the master extractor. When that happens, RDF (or more
specifically, the master receiver process) may falsely appear to be hung. As soon as the
auxiliary extractor has caught up, however, the TMF shutdown operation proceeds.
Takeover Ramifications
If an auxiliary extractor is running behind the master extractor when you issue a
TAKEOVER command, a transaction just committed on the primary system (and who’s
commit record was received by the master receiver) could be backed out on the backup
system.
This could happen under the following circumstances:
•
In addition to the MAT, you have configured RDF to protect one or more auxiliary
audit trails.
Note. Data volumes on the backup system need not be mapped to the same audit trail as on
the primary system. If a data volume on the primary system is mapped to the MAT, for
example, the corresponding updater volume on the backup system can be mapped to an
auxiliary audit trail.