Upgrading a PowerHA SystemMirror cluster

These topics provide instructions for upgrading an existing PowerHA® SystemMirror® cluster configuration.

Supported upgrade PowerHA SystemMirror versions
From any earlier versions of PowerHA SystemMirror, you can upgrade to the subsequent three versions of PowerHA SystemMirror only. If you want to upgrade to an even higher version of PowerHA SystemMirror, you must first upgrade to an intermediate PowerHA SystemMirror version.
Migrating from PowerHA SystemMirror 6.1 to PowerHA SystemMirror 7.1.3 or PowerHA SystemMirror 7.2.0
To migrate from PowerHA SystemMirror Version 6.1 to PowerHA SystemMirror 7.1.3 or PowerHA SystemMirror 7.2.0, you must update the version of the AIX® operating system for nodes in the cluster.
Upgrading prerequisites
Before you upgrade to PowerHA SystemMirror, you must have a basic knowledge of high-level PowerHA SystemMirror concepts and low-level tasks, such as planning, maintenance, and troubleshooting, because the upgrade process builds on that knowledge.
Planning for an upgrade
Before you can start doing an update, you must plan correctly for the upgrade.
Upgrade do's and don'ts
This section lists the major tasks to do during or before an upgrade, and it also lists what not to do.
Performing a rolling migration
You can upgrade a PowerHA SystemMirror cluster while keeping your applications running and available. During the upgrade process, a new version of the software is installed on each cluster node while the remaining nodes continue to run the earlier version. In this hybrid state, PowerHA SystemMirror continues to respond to cluster events.
Upgrading PowerHA SystemMirror using a snapshot
You can upgrade a cluster by using a cluster snapshot that was created on the configuration with an earlier version of PowerHA SystemMirror. This upgrade path requires cluster services to be offline simultaneously on all nodes. As a result, your applications will not be highly available during the upgrade.
Upgrading an offline cluster for PowerHA SystemMirror
You can take cluster services offline on all of the nodes and then update the cluster definitions individually on each node.
Upgrade PowerHA SystemMirror using the cl_ezupdate command
You can use the cl_ezupdate command to update the software for the entire cluster or a subset of nodes in the cluster, often without disrupting workloads.
Additional migration tasks
After you complete the upgrade, you might need to complete additional tasks.
Verifying the success of your migration
Now that all nodes have been migrated, you need to complete the necessary tasks to ensure that everything is working correctly.
Troubleshooting your migration
Making configuration changes is not supported during the migration process. If you try to change the cluster topology or resources when migration is incomplete, the synchronization process fails and you get an error.
Recovering your previous version of PowerHA SystemMirror
These topics discuss how to completely undo your migration and recover your previous version of PowerHA SystemMirror.

Parent topic: Installing PowerHA SystemMirror