Availability Guide for Application Design

Data Protection and Recovery
Availability Guide for Application Design—525637-004
4-15
Remote Duplicate Transactions
To guard against failure of the switching system, an alternate switching system is
available and associated with the backup site. The alternate switching system is able
to take over at any time because of the status information it receives from the primary
switching system with each transaction.
When the old primary site is restored, the following tasks will recover its database
without stopping the application:
•
Perform TMF file recovery to synchronize the old primary system’s database with
the old backup system’s database at the time the backup took over. This step is
necessary because of the time lag between committing transactions at the primary
site and copying the audit-trail records to the backup site.
•
Reconfigure the RDF product to operate in the reverse direction; all audit-trail
records on the old backup system are now copied to the old primary system.