Migrating a Service Group

In the global cluster setup, consider a case where the primary cluster suffers a failure. The Oracle service group cannot fail over in the local cluster and must fail over globally, to a node in another cluster.

In this situation, VCS sends an alert indicating that the group cannot fail over anywhere in the local cluster.

An administrator can take action by bringing the group online in the remote cluster.

The RVGPrimary agent ensures that VVR volumes are made writable and the DNS agent ensures that name services are resolved to the remote site. The application can be started at the remote site.

Switching the Service Group

Before switching the application to the primary site, you must resynchronize any changed data from the active Secondary site since the failover. This can be done manually through VVR or by running a VCS action from the RVGPrimary resource.

  To switch the service group

1. In the Service Groups tab of the configuration tree, right-click the resource.
2. Click Actions.
3. Specify the details of the action:
   1. From the Action list, choose fbsync.
   2. Click the system on which to execute the action.
   3. Click OK.

   This begins a fast-failback of the replicated data set. You can monitor the value of the ResourceInfo attribute for the RVG resource to determine when the resynchronization has completed.

4. Once the resynchronization completes, switch the service group to the primary cluster.
   1. In the Service Groups tab of the Cluster Explorer configuration tree, right-click the service group.
   2. Click Switch To, and click Remote switch.
   3. In the Switch global group dialog box, click the cluster to switch the group. Click the specific system, or click Any System, and click OK.

Declaring the Type of Failure

If a disaster disables all processing power in your primary data center, heartbeats from the failover site to the primary data center fail. VCS sends an alert signalling cluster failure. If you choose to take action on this failure, VCS prompts you to declare the type of failure.

You can choose one of the following options to declare the failure:

• Disaster, implying permanent loss of the primary data center
• Outage, implying the primary may return to its current form in some time
• Disconnect, implying a split-brain condition; both clusters are up, but the link between them is broken
• Replica, implying that data on the takeover target has been made consistent from a backup source and that the RVGPrimary can initiate a takeover when the service group is brought online. This option applies to VVR environments only.

You can select the groups to be failed over to the local cluster, in which case VCS brings the selected groups online on a node based on the group's FailOverPolicy attribute. It also marks the groups as being OFFLINE in the other cluster. If you do not select any service groups to fail over, VCS takes no action except implicitly marking the service groups as offline in the failed cluster.