RDF/IMP and IMPX System Management Manual (RDF 1.4+)

Introducing RDF
HP NonStop RDF/IMP and IMPX System Management Manual—524388-001
1-15
Monitor Process
Updating can be explicitly enabled or disabled through RDFCOM commands, as
described later in this manual. If takeover performance is critical, you should run RDF
with updating enabled. If updating is disabled, it is possible for the image trails to fill up;
also, it may take significant time for the updaters to apply all audit information when a
takeover operation is started.
The monitor, extractor, receiver, updater, and purger processes run as process pairs.
Monitor Process
The monitor process is a process pair that normally runs on the primary system. This
process is responsible for starting, stopping, and monitoring all other RDF processes
on the primary and backup systems.
Extractor Process
An extractor process is a process pair that runs on the primary system. Each extractor
process reads an audit trail (the MAT or a particular auxiliary audit trail), filters out audit
records not relevant to the backup database, and then transmits the relevant audit
records over the Expand network to an associated receiver process on the backup
system, as shown in Figure 1-5.
Reading large amounts of data from the MAT, the extractor process stores the
following records for subsequent transmission to the backup system:
•
All transaction state records
•
TMP control point records
•
Records generated by TMF undo processing
•
Audit records associated with files protected by RDF
•
For Enscribe files (DDL operations) only, the following file-label modification
records:
CREATE
PURGE (if REPICATEPURGE is enabled)
PURGEDATA
ALTER MAXEXTENTS
•
For SQL files (DDL operations) only, the following file-label modification records:
PURGEDATA
•
Stop-RDF-Updater records
•
TMF shutdown records
Note. The discussion and figure that follow are both oriented to the extractor associated with
the MAT. For information about protecting auxiliary audit trails, see Section 12, Auxiliary Audit
Trai ls .