RDF/IMP and IMPX System Management Manual (RDF 1.3+)

Managing RDF
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
5-19
Issuing the TAKEOVER Command
3. To proceed with the takeover operation, enter Y or YES.
To abort the takeover operation, enter N or NO.
After you enter your response, RDFCOM returns its prompt. Then you can use the
STATUS RDF command to determine the status of the takeover operation. If the
takeover operation is still in progress, RDF displays the current state as
“TAKEOVER IN PROGRESS.”
When the takeover operation finishes, RDF displays the following message in
response to the STATUS RDF command:
STATUS RDF (\SANFRAN -> \TORONTO) is NOT running. An RDF
TAKEOVER has completed.
Takeover Failure
If a double CPU failure occurs and the receiver process pair or an updater process pair
fails during a takeover operation, you can resume the operation just by entering the
TAKEOVER command through RDFCOM again.
Monitor Considerations
Whether the RDF monitor was started when the initial TAKEOVER command was
executed or not, this process is always started when the TAKEOVER command is
reissued.
Updater Considerations
When the receiver shuts down at the end of the takeover operation, it examines the
context record of each updater process to determine if that updater has processed all
applicable audit data through the end-of-file in the image trail. If all updaters have
processed through the end-of-file, the receiver logs a 724 message to the EMS event log,
indicating that the takeover operation completed successfully. But if it determines that
one or more updaters have terminated prematurely, the receiver logs RDF Message 726
for each updater that failed and then logs RDF Message 725, a general message
indicating that the takeover operation did not complete successfully. If these messages
appear in the EMS event log, you must reissue the TAKEOVER command.
Takeover and File Recovery
A long-standing problem with the RDF product has been that when the primary system
came back online after you had done a takeover and switched your applications to the
backup system, you had to perform a complete database synchronization before your
applications could be switched back to the primary.
That no longer is necessary.
Note. After the takeover has completed, you should check the EMS event log to ascertain
whether the takeover was successful or not. Message 724 indicates the takeover was
completed successfully; message 725 indicates that it was not. If it was not successful, try to
determine the problem and correct it, and then restart the takeover.