Configuring an Oracle RAC One Node

In a RAC one node configuration, a single instance of an Oracle RAC database runs on one node of the cluster while the second instance is in a cold standby mode. If there is a failure or fault in the first node and the instance cannot be restarted on the same node, then RAC One node cluster detects it and relocates the instance to the other node. The benefit of this feature is that it automates the instance relocation without any downtime and manual intervention. In this configuration, you must use unique instance names while configuring instances on both nodes.

See Creating a RAC Client for more information.

The RAC one nodes can have multiple ways of running the instances.

1st - Node 1 running instance_1

2nd - Node 1 running instance_2

3rd - Node 2 running instance_2

4th - Node 2 running instance_1

When you configure a RAC one database in Commvault, you must configure unique instances, by associating the instances with physical clients.  Commvault automatically detects the instances relocation and connects the available instance.

Example of Instance and Client Combination

1st - Node 1 running instance_1

2nd - Node 1 running instance_2

See Can you restore from a RAC One Node in a multiple node configuration for important considerations that you must follow when you restore from a RAC One Node.

Note: Use the  for Restore option when you perform a restore.


  1. From the CommCell Browser, navigate to Client Computers > RAC_Client.
  2. Right-click the instance and click Properties.

    The Instance Properties dialog box is displayed.

  3. On the Details tab, click Add.

    The Add Instance dialog box is displayed.

  4. In the Instance Physical Client list, select the Instance Physical client name.
  5. In the Instance (ORACLE SID) box, type the instance names for the instances in the other nodes. For example, type the Instance name as testracdb_1 for Instance_1. Type the Instance name as testracdb_2 for Instance_2.
  6. In the Database Name box, type the name of the Oracle RAC database (for example, testracdb) to which you are assigning this client.
  7. In the Connect String box, type the Scan Connect String (SYS login).

    Best Practice: Use the scan host name in the connect because the backup process requires pre-identified node for backup resource reservation.


    Node 1 Connect String: sys/password@scan-hostname:port/servicename

    Node 2 Connect String: sys/password@ scan-hostname:port/servicename

    You must use scan connect to configure the RAC one node in a multiple node environment.

  8.  Click OK to close the warning dialog box.
  9. In the Oracle Home box, type the Oracle installed path.
  10. In the TNS_ADMIN Folder box, type the TNS ADMIN folder name.
  11. On the Storage Device tab, in the Storage Policy used for user command backup of data box, select a storage policy.
  12. On the Log Backup tab, in the Storage Policy used for all Archive Log backups box, select a storage policy name.
  13. Click OK.


The RAC database name is "testracdb".

The instances are "testracdb_1" and "testracdb_2".

If Node 1 is active, the instance "testracdb_1" runs on Node 1. If the instance is relocated to Node 2 due to a failure or abnormal termination, then the instance "testracdb_1" runs on Node 2.

Another option is to have Node 2 running "testracdb_2". If Node 2 fails to start "testracdb_2", it is relocated to Node 1. In this case, Node 1 runs "testracdb_2".

The Commvault software supports the above configurations. In the CommCell Console, configure "testracdb_1" under Node 1 and "testracdb_2" under Node 2.

By default, when you discover or create an Oracle instance, the Commvault software automatically creates a default data subclient and a default archive log subclient.

Last modified: 10/29/2018 1:17:12 PM