RDF/IMP and IMPX System Management Manual (RDF 1.4+)

Triple Contingency
HP NonStop RDF/IMP and IMPX System Management Manual—524388-001
10-7
COPYAUDIT Restartability
RDFCOM turns off the receiver’s takeover completed flag and issues a message telling
you that the COPYAUDIT operation has completed successfully and you must initiate
another takeover on \C. Issue a TAKEOVER command on \C. If the takeover
completes successfully (the receiver logs an RDF message 724 followed by a 735
message containing the same detail as in the 735 message associated with the
takeover on \B), the two databases are logically identical.
At that point you can initialize, configure, and start RDF on both systems and then
resume application processing on the new primary system with full RDF protection.
COPYAUDIT Restartability
The COPYAUDIT command is restartable.
If an error condition aborts execution of a COPYAUDIT command, you merely correct
the condition and then reissue the command. Upon restart, RDFCOM quickly checks
the local system image files it had previously created to be sure they are still correct,
deletes the file it was working on at the time of the error condition, and then resumes
copying. Because it keeps track of where it was in the COPYAUDIT operation,
RDFCOM does not have to recopy the previously copied image files.
RDFCOM abends if it encounters network problems while searching the remote image
trails for missing audit information. If that happens, RDFCOM logs a message to the
EMS event log, but not to the home terminal.
If RDFCOM encounters network problems during any other phase of COPYAUDIT
execution, it does not abend. Instead, it logs a message to the home terminal and
aborts the COPYAUDIT command.
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.
3. Ensure that the two RDF configurations are configured identically with respect to
the two backup systems (with the few minor exceptions noted earlier in this
section).
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 do as follows:
1. Issue a TAKEOVER command on both backup systems.