RDF System Management Manual for H-Series RVUs (RDF 1.8)

(and therefore be eligible for purging), but, because the RETAINCOUNT is set to three, the purger
process can only purge AA000010 (it must keep AA000011 and AA000012 on disk). Thus, as long
as the RTD times of the extractors on the two backup systems are less than 36 hours apart, the
triple contingency protocol will work successfully.
Similarly, if you believe the two receiver processes will never be more than 48 hours apart in
their RDF processing and your image trail file sizes are such that approximately 20 rollovers
occur every 24 hours, then you should set the RETAINCOUNT to 40 on both backup systems.
You set the RETAINCOUNT parameter by issuing this command:
SET PURGER RETAINCOUNT num
where num is a number within the range 2 through 5000. The default is 2.
You can alter the RETAINCOUNT only when RDF is stopped.
You alter the RETAINCOUNT parameter by issuing this command:
ALTER PURGER RETAINCOUNT num
where num is once again within the range 2 through 5000. (Before entering this command,
however, you must first stop RDF.)
The COPYAUDIT Command
If the primary system fails, you must execute two takeovers: one on each backup system. Upon
successful completion of both takeovers (signalled by a 724 message in the EMS event log of each
backup system), the databases on the two backup systems will almost assuredly be different:
one of the systems will have been further ahead of the other in its RDF processing when the
failure occurred.
The COPYAUDIT command copies missing audit information from the backup system that was
further ahead in its RDF processing (had the most amount of audit data) to the system that was
further behind (had the least amount of audit data).
Upon successful completion of the two takeovers, examine the EMS event log on both backup
systems for a 735 message. That message, which follows the 724 message in the log, specifies the
last position in the MAT that was seen by the receiver process. Compare the MAT positions in
the two 735 messages and determine which of the two systems was further behind in its RDF
processing when the failure occurred (that is, which system had received the least amount of
audit data from the extractor by the time the primary system was lost). Then issue a COPYAUDIT
command on that system, specifying the name of the other backup system and its RDF control
subvolume.
The syntax of the COPYAUDIT command is:
COPYAUDIT, REMOTESYS sys, REMOTECONTROLSUBVOL subvol
where sys is the name of the other system (the backup system that has the most amount of audit
information) and subvol is the name of the RDF control subvolume on that system.
For this discussion, assume that you have established two RDF configurations:
RDF Configuration #1:
\A ------------------> \B
(The RDF control subvolume is A1 on both systems.)
RDF Configuration #2:
\A ------------------> \C
(The RDF control subvolume is A2 on both systems.)
Assume you have lost the original primary system (\A), you have successfully completed a
takeover on both backup systems (\B and \C), and the MAT positions displayed by the respective
735 messages are:
\B: 735 LAST MAT POSITION: Sno 10, Rba 100500000
\C: 735 LAST MAT POSITION: Sno 10, Rba 100000000
258 Triple Contingency