Hardware Requirements; Software Requirements - HP NonStop RDF J-series RVUs Management Manual

(that is, which system had received the least amount of audit data from the extractor by the
time the primary system was lost).
• On the backup system that was further behind (had the least amount of audit data), issue
the COPYAUDIT command specifying the name of the other backup system and its RDF
control subvolume. That command copies over all missing audit records from the designated
system.
• Upon successful completion of the COPYAUDIT operation, do a second takeover on that
system. When the second takeover has completed successfully, initialize and configure the
two backup systems as a new primary-backup pair (either system can be the primary) and
then restart application processing on the new primary system.
The remainder of this chapter discusses the hardware and software requirements, the
RETAINCOUNT parameter, and the COPYAUDIT command in detail.
WARNING!
obey the instructions and caveats presented in this chapter.

Hardware Requirements

Both backup systems should have similar hardware with respect to RDF operation (in particular,
the data volumes and image trails must be identical between the two systems). It is also strongly
recommended that the Expand bandwidth between the primary and backup systems be the same
for both configurations, as well as between the two backup systems.

Software Requirements

You must be running the same release of RDF on all three systems (the primary system and
both backup systems).
The two RDF subsystems should be configured identically with respect to both backup
systems.
At the very least, these key fields must be identical on both backup systems:
• The primary database volumes being protected
• The mapping of data volumes between the primary and backup system
• The number of image trails
• The mapping of updaters to image trails
• The image trail extents
• The purger RETAINCOUNT
Other fields, such as process names and process priorities, do not need to be identical on the two
backup systems.
272 Triple Contingency
To be able to use the triple contingency feature, it is imperative that you carefully