In this scenario:

NODEA is the Primary cluster node with the production copy of the IASP.
NODEB is the Backup cluster node. It does not currently own a copy of the IASP.
LUN-Level switching is configured between NODEA and NODEB.

This example includes instructions for upgrading the operating system in a PowerHA environment with LUN-Level Switching. For upgrading in an environment that using replication, such as Geographic Mirroring, Metro Mirror, or Global Mirror, see Upgrading or Updating the Operating System in a PowerHA Environment with Replication.

Procedure

Part 1 - Upgrading the Backup Cluster Node

Begin with the environment pictured above.
If the status of the CRG is anything other than Inactive, end the cluster resource group with the ENDCRG command. In this scenario, the command is: ENDCRG CRG(MYCRG)
End clustering on the Backup Node. This is NODEB in the example by using the ENDCLUNOD command. In this scenario, the command is: ENDCLUNOD NODE(NODEB)
Upgrade NODEB to the new software level. This new level could be for program temporary fixes (PTFs) or to a new release. If upgrading to a new release see Upgrading or replacing IBM i and related software for details.

It is important to ensure that NODEB is at a high enough PTF level to ensure the node can properly start and join the PowerHA cluster. See PowerHA & Cluster Version Compatibility for additional information on cross-version and modification level compatibilities. Use the DSPCLUINF command to view the potential PowerHA version of the nodes to ensure compatibility.

If clustering is inactive on NODEB, start clustering by using the STRCLUNOD command. For example: STRCLUNOD NODE(NODEB)
If the cluster resource group is inactive, start the Cluster Resource Group using the STRCRG command. For example: STRCRG CRG(MYCRG)

Part 2 - Switch users to the Backup Node

Now that the update to the node is completed, users can be switched to the backup node to make it the new primary node. This will enable the original primary node to be upgraded while users continue to access Node B.

Perform a switchover using the CHGCRGPRI command. For example: CHGCRGPRI CRG(MYCRG)

Part 3 - Upgrading the Original Primary Node

If the status of the CRG is anything other than Inactive, end the cluster resource group with the ENDCRG command. In this scenario, the command is: ENDCRG CRG(MYCRG)
End clustering on the original primary node. This is NODEA in the example by using the ENDCLUNOD command. In this scenario, the command is: ENDCLUNOD NODE(NODEA)
Upgrade NODEA to the new software level. This new level could be for program temporary fixes (PTFs) or to a new release. If upgrading to a new release see Upgrading or replacing IBM i and related software for details.
If clustering is inactive on NODEA, start clustering by using the STRCLUNOD command. For example: STRCLUNOD NODE(NODEA)
If the cluster resource group is inactive, start the Cluster Resource Group using the STRCRG command. For example: STRCRG CRG(MYCRG)

Part 4 - Switch Users Back to the Original Primary Node

Now that everything has been upgraded, users can be switched back to the original primary node, NODEA in this example.

Perform a switchover using the CHGCRGPRI command. For example: CHGCRGPRI CRG(MYCRG)

Results

Both nodes in the PowerHA environment have been upgraded; the outage users experienced was reduced to only the amount of time it takes to perform a switchover in a PowerHA enviornment.

IBM Partnership