Failover process for synchronous PPRC in a planned outage

The following sequence of events would take place in a planned outage, such as might occur when preventive maintenance is performed at the primary site.

Figure 1. Failover in a Synchronous PPRC Environment

1. Quiesce applications at the primary site to reduce the risk of data loss.
2. Suspend the PPRC pairs using the PPRC Suspend command.
3. Issue the PPRC Establish Pair command to the B volume as the DEVN, specifying the FAILOVER ACTION and reversing the original PRIMARY and SECONDARY parameters. This establishes the B volumes as suspended primaries, activates change recording on the B volumes, and releases write inhibit on the B volumes.
4. If desired, FlashCopy® the B volume suspended primaries to C volumes to provide safe copies for interim disaster recovery protection.
5. Restart applications at the recovery site.