Summary - HP NonStop RDF J-series RVUs Management Manual

Summary

To be able to use the triple contingency feature, you must:
1. Establish two RDF configurations with the same primary system and separate backup
systems.
2. Ensure that the hardware configurations of the two backup systems are identical with regard
to data volumes and image trail volumes.
3. Ensure that the data volumes and image trails of the two RDF configurations are configured
identically with respect to the two backup systems (with the few minor exceptions noted
earlier in this chapter).
4. Set an adequate purger RETAINCOUNT parameter on the backup systems (it must be the
same on both).
Upon loss of the primary system, you must:
1. Issue a TAKEOVER command on both backup systems.
2. When the takeovers have completed successfully, examine the EMS event log on both backup
systems for a 735 message to determine which system is missing audit records.
3. On the system with the least amount of audit records, issue a COPYAUDIT command
specifying the name of the other backup system and its RDF control subvolume.
4. When the COPYAUDIT command has completed successfully, issue a second TAKEOVER
command on that same system.
5. Initialize, configure, and start RDF on whichever system you want to be the primary in the
new configuration.
6. Start application processing on the new primary system.
Summary 277