CRG Failover HyperSwap and LUN switching

In the case of a planned outage of the system server, a CRG failover can be initiated.

The following conditions must be met before the failover is initiated.
  1. Both DS8000s must be accessible by PowerHA® through DSCLI.
  2. None of the HyperSwap® relationships in the IASP can have two primary volumes. This is shown by XXXX for the copy status when a Display HyperSwap Status or Work with HyperSwap Status command is run for the IASP.
CRG Failover with  HyperSwap and LUN switching example.

In the figure, first the CRG failover takes place, resulting in Number 2, where IASP1 is now varied on to IBM i B. If affinity was defined by the ADDHACFGD command and the affinity is not correct after the CRG failover, then PowerHA will also initiate a HyperSwap switchover of IASP1, shown in Number 3.

If a HyperSwap switchover cannot be completed due to some reason such as HyperSwap being suspended or not fully synchronized, the CRG failover completes and a diagnostic message is sent indicating that the HyperSwap switchover failed.