For a two-node Oracle RAC database with each instance running on two VMs on separate ESXi hosts, you can migrate one VM with the Oracle RAC database instance from one ESXi host to another. During a cold migration, the VM is offline and the Oracle RAC database instance that is running in the VM guest is down. During a hot migration, both the VM and the Oracle RAC database instance are online and operational. Use the hot migration feature to avoid a planned downtime of the database instance during server hardware or software maintenance of the ESXi host by moving a live VM with its operational Oracle database instance to a different ESXi host.
To launch a hot migration by vMotion:
The migration options are displayed, as shown in the following figure:
The migration wizard validates the compatibility of the target resource. If any compatibility problem exists, it is displayed in the Compatibility panel. Resolve the issue or select another host or cluster.
We performed this check to confirm that the database instance was functioning during the migration. The database instance showed 10 active connections from TPC-C users. This number was the same as before the migration, as shown in the following figure:
We ran the HammerDB OLTP workload test on both RAC database nodes during the migration.
The following figures show the database throughput transactions per minute (TPM) before, during, and after vMotion migrations. As shown, no performance change occurred due to vMotion operation.
The following figures show the VM2 migration.
Before the migration, VM2 was running on ESXi host2 (IP address ending with 23):
After the migration, VM2 was moved to ESXi host1 (IP address ending with 22):
We also reviewed the CPU utilization changes for both ESXi hosts.
The following figure shows the CPU utilization of ESXi host2 (with an IP address ending in 23) as:
The following figure shows the CPU utilization of ESXi host1 (with an IP address ending 22), the host to which the VM was migrated, as: