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The diagrams below depict the stages of a CRG switchover in an HyperSwap environment with Global Mirror replication.
Begin with the environment in normal operation as described above.
Type in the following command to initiate the Global Mirror switchover from the IBM i NODE_1 system to the NODE_2 system in the cluster.
Code Block CHGCRGPRI CLUSTER(PWRHA_CLU) CRG(HYSGMIRCRG)This indicates to PowerHA that the user wants to change the primary node in the cluster resource group. In the scenario provided, this changes the direction of the Global Mirror, changing the primary DS8000 from DS8000 A to DS8000 B and the primary system from NODE_1 to NODE_2.
The command switches the primary system from IBM i production system with DS8000 A to the NODE_2 system and DS8000 C. The Global Mirror configuration will replicate in the opposite direction after it is started.
As the Global Mirror configuration reversed from DS8000 C to DS8000 A, the HyperSwap replication connection from DS8000 A to DS8000 B changes the from a synchronous to an asynchronous connection because it now exists at the target side of the Global Mirror.
Result
The switchover should complete successfully. Notice the primary has changed and the Global Mirror is replicating in the opposite direction.
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Figure 1. Changing the CRG primary in a CRG switchover within a HyperSwap with Global Mirror configuration
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