Planning multiple-release clusters

If you are creating a cluster that includes nodes at multiple cluster versions, then certain steps are required when you create the cluster.

By default, the current cluster version is set to the potential cluster version of the first node added to the cluster. This approach is appropriate if this node is at the lowest version level to be in the cluster. However, if this node is at a later version level, then you cannot add nodes with a lower version level. The alternative is to use the target cluster version value when you create a cluster to set the current cluster version to one less than the potential cluster version of the first node added to the cluster.

Note: If you are using the IBM® PowerHA® SystemMirror® for i licensed program, it is required on all systems within the cluster.

For example, consider the case where a two-node cluster is to be created. The nodes for this cluster follow:

Node identifier	Release	Potential cluster version
Node A	V7R1	7
Node B	V7R2	8

If the cluster is to be created from Node B, care must be taken to indicate that this will be a mixed-release cluster. The target cluster version must be set to indicate that the nodes of the cluster will communicate at one less than the requesting node's potential node version.