RDF System Management Manual

Managing RDF
HP NonStop RDF System Management Manual—524388-003
5-13
Stopping RDF
Note that you should not perform a file recovery to a timestamp, first purge, or
TOMATPOSITION on your backup system if the location occurs prior to an RDF
takeover location. Those file recovery operations normally are used to recover a
database that has been corrupted.
Under normal circumstances, the best way to recover the backup database is to
resynchronize it with your primary database. Because that can involve significant time
and effort, you should consider using the following method instead (assume that the
system clocks on the primary and backup systems are set to the same time):
•
Stop RDF.
•
Perform file recovery to a timestamp on the backup system.
•
Determine the duration of the longest running transaction on your primary system.
Subtract this amount of time from the time used for the file recovery operation.
If you don't know the duration of the longest transaction, it is better to overestimate
than to underestimate (use an arbitrary number, such as 10 minutes). There is
nothing wrong with initializing RDF to a point further back in time than is necessary.
•
On the primary system, reinitialize RDF with the INITTIME option, specifying the
calculated timestamp from the above step.
•
Restart RDF.
When the updaters have caught up with transaction activity on the primary system, the
backup database is once again synchronized with your primary database.
Stopping RDF
If the communications lines between the primary and backup systems are up, there are
two ways to stop RDF:
1. Issue a STOP RDF command on the primary system.
2. Issue a TMFCOM STOP TMF command on the primary system. After the RDF
updaters have reached the TMF shutdown record, RDF stops and then TMF stops.
If the communications lines between the two systems are down and you want to stop
RDF, you must issue the STOP RDF command on both the primary and backup
systems.
Note that stopping RDF leaves the backup database in an inconsistent state and also
leaves the audit trail file last opened by the extractor pinned.
Caution. If the primary system crashes, RDF processes on the backup system remain
running. If you do not execute a takeover and are able to bring the primary system back up,
you must stop the RDF processes on the backup system before you restart RDF on the
primary system. While the primary is down issue STOP RDF on backup. Otherwise, issue the
following TACL command on the backup system: STATUS *, PROG, $SYSTEM.RDF.*, STOP
(assuming the RDF SOFTWARELOC is $SYSTEM.RDF).