The REC function supports parallel mode for processing on the source units and target units. It must be borne in mind here that when remote replication is stopped (/HOLD-REMOTE-COPY) the target units are automatically made available for system accesses.
When remote replication is stopped, failure tests can be conducted on the source units without interrupting the applications in the local system. The test scenario differs from a genuine failure in that the local storage system is active during the test. Processing on the source units takes place in the local system. The recovery procedures are tested in the standby system using the target units.
Overview
A recovery procedure consists of the following steps:
Failure detection
A check to establish whether processing can be continued on the local system (with the source units)
Interrupting remote copy mode and enabling the target path
If required, shutdown of local system
Startup of the standby system and continuation of processing(IPL, attach, import, change network node, restart applications)
The actions needed to interrupt remote copy mode and enable the target path are described on "Interrupting remote copy mode and enabling the target path". The actions needed to recover the source and target units are described on "Reconstructing the source and target units after the test".