RDF System Management Manual for J-series and H-series RVUs (RDF Update 13)

Figure 4 RDF Subsystem Processes
Application
Processes
RDFCOM
Monitor
$MON1
Extractor
$EXT
Primary Secondary
TMF Product
Master
Audit Trail
Master
Image
Trail
Replicated
Database
Secondary
Image
Trail
Audited
Database
Updaters
$U01-$U0n
Purger $PRG
Receiver
$RCV
Primary System Processes
On the primary system:
• The monitor process coordinates most RDFCOM commands involving the main RDF processes
(for example, start and stop).
• 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, transforms the audit record into an
image record, and then transmits the image records to an associated receiver process on the
backup system. Some control information for synchronizing the extractor and receiver process
pair is included each time the extractor process transmits the audit records.
Backup System Processes
On the backup system:
• There is one receiver process for each configured extractor process. A receiver accepts the
image records from its extractor, sorts them, and then writes them to the appropriate RDF
image trail.
• There is one updater process for each primary system volume being protected by RDF. Updater
processes read image records from their RDF image trails and pass them to the disk process
so that the disk process can perform the logical REDO operations. The backup database is
updated in cache each time the disk process performs a logical REDO operation requested
by an updater process.
• The purger process interacts with the updaters to determine when image files can be purged,
and also determines which transactions updaters must undo for takeover and stop-update-to-time
operations.
RDF Operations
RDF can be run with updating of the backup database either enabled or disabled.
RDF Operations 31