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

Introducing RDF
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
1-8
Tasks
•
RDF issues an informational, warning, or error message (including RTD warning
messages)
•
An RDF process takeover occurs
•
Control switches from the primary to the backup database
•
A SQL/MP DDL operation using the WITH SHARED ACCESS option is
performed
•
An exception record is written
You can peruse messages in the EMS log on your terminal screen by using Viewpoint or
whatever other tool you normally use for monitoring $0. Note that when doing that,
however, you are dealing with the entire EMS log (not just RDF messages).
To isolate RDF messages from the rest of the EMS log, you can use the supplied EMS
filter RDFFLTO with an EMS printing distributor to produce an intermediate entry-
sequenced file which you then can scan using the RDFSCAN utility.
Using RDFSCAN commands, you can specify:
•
A starting point for scanning the intermediate RDF message file
•
How many records to scan
•
Text to search for in the file
Tasks and examples for using RDFSCAN commands appear throughout the manual.
Reference information for all commands appears in Section 9, Entering RDFSCAN
Commands.
Tasks
To maintain a duplicate of the primary database on the backup system, RDF performs
four fundamental tasks:
•
On the primary system, the extractor process captures audit information from the
TMF MAT and, optionally, from auxiliary audit trails.
•
On the primary system, the extractor process filters out audit information that is not
relevant to the backup database (audit information for volumes not protected by
RDF) and then transmits the relevant audit information to the backup system. These
records on the backup system are called image records.
•
On the backup system, the receiver process accepts the filtered audit information,
sorts it, and then writes it to the appropriate RDF image trail.
•
On the backup system, updater processes read the records from their image trail files
and pass them to the disk process. The disk process interprets them and performs the
logical REDO operation for each record, updating rows or records in the backup
database.