Migrating a peer domain to a CAA environment

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When Cluster-Aware AIX® (CAA) is available, an existing peer domain can be migrated so that it operates based on CAA, rather than operating autonomously.

As part of the migration process, a CAA cluster is defined containing the node complement of the peer domain that is being migrated. The interface resource set defined in the IBM.NetworkInterface class might change slightly because the view of interfaces on cluster nodes provided by CAA might differ slightly from that acquired by the configuration resource manager from the operating system in a peer domain that is not running in a CAA environment.

Planning the migration of an existing peer domain to a CAA environment

When deciding whether to migrate an existing peer domain to a CAA environment, the constraints that only one CAA cluster can be defined at a time, that there will always be a peer domain corresponding to it defined and online, and that no other peer domains can be defined, are significant. Therefore, consider the following:
  • Do not define a CAA cluster before deciding whether any existing peer domain should be migrated to a CAA environment. If a CAA cluster is defined independent of any existing peer domains, a new peer domain corresponding to it is created, and any existing peer domains are deleted.
  • If multiple peer domains are defined on a collection of nodes, when CAA is installed and becomes available, only one of those can be migrated to CAA, and the rest will be deleted as part of the migration process. If more than one existing peer domain must be maintained, none can be migrated to CAA.
  • When migrating a peer domain to a CAA environment, a physical volume that is shared by all nodes in the peer domain must be provided to support the resulting CAA cluster's repository disk function. Optionally, multiple sets of physical volumes shared by all of the nodes in the peer domain can be identified for application use.

Carrying out migration to a CAA environment

To migrate a peer domain to a CAA cluster after the required shared physical volume sets have been identified (hdisk1 and hdisk2, for example) and the peer domain is online, enter: 

CT_MANAGEMENT_SCOPE=2 runact -c IBM.PeerDomain MigrateToCAA \
[QuorumType=quorum_type] ReposDisks=hdisk1 \
[SharedDisks=hdisk2,...]
If the QuorumType attribute is not present, the default value is set to normal or strong quorum (0) in the migrated domain.

This step could take several minutes to complete as the CAA cluster is created and the peer domain nodes run a protocol to switch over to the CAA environment in an orderly fashion. If any part of the migration step fails, the error is reflected in a message and the peer domain continues to operate autonomously as it did prior to migration.

See the AIX Installation and Migration Guide for information about migration of an existing CAA cluster to new levels of AIX.