Performing a HyperSwap Switchover

This scenario shows what takes place in a HyperSwap environment with Global Mirror when a HyperSwap switchover takes place

Before you begin

This scenario uses the configuration created in the Configure HyperSwap with Global Mirror using Copy Services Manager (CSM). Review this configuration before proceeding with the switchover operation.

In order for the switchover operation to succeed four settings must be configured:

1. clustering must be active on the node that currently controls the IASP.
2. all disk units in the IASP must be configured for the HyperSwap relationship.
3. all of the HyperSwap relationships in the IASP must be synchronized.
4. every HyperSwap relationship in the IASP must be replicating in the same direction. All disk units must have the same primary DS8000.

If these conditions are not in place, the HyperSwap switchover operation will fail.

About this task

In this scenario, the IASP, named IASP_1, on DS8000 A is configured for HyperSwap. All disk units in the IASP on DS8000 A correspond to disk units in DS8000 B and are linked across a synchronous connection. Both storage units are attached to the IBM i system named NODE_1. In addition to being configured for HyperSwap, the storage unit also is configured for Global Mirror to a DR site with DS8000 C and a separate IBM i system named NODE_2.

Procedure

The diagrams below depict the stages of a HyperSwap switchover in an environment with Global Mirror replication.

1. Begin with the environment in normal operation as described above.
2. Type in the following command to initiate a switchover from DS8000 A to DS8000 B.

   CHGHYSSTS OPTION(*SWAP) NODE(NODE_1) ASPDEV(IASP_1)

   This indicates to PowerHA that the user wants to swap the HyperSwap relationship, changing the primary from DS8000 A to DS8000 B.
3. The command switches the HyperSwap primary from DS8000 A to DS8000 B with near-zero downtime.
4. PowerHA switches the Global Mirror link to keep the Global Mirror replication from the primary, now DS8000 B to DS8000 C.

Result

The switchover should complete successfully. Use the DSPHYSSTS to confirm the changes.

Example

Figure 1. HyperSwap switchover within a HyperSwap with Global Mirror configuration: