Using DBCA in Interactive Mode to Delete Instances from Nodes

To delete an instance using DBCA in interactive mode, perform the following steps:

1. Verify there is a current backup of OCR.

   Run the ocrconfig -showbackup command to ensure there is a valid backup.

2. Start DBCA.

   Start DBCA on a node other than the node that hosts the instance that you want to delete. The database and the instance that you plan to delete should continue to be started and running during this step.

3. On the DBCA Operations page, select Instance Management, click Next, and DBCA displays the Instance Management page.

4. On the Instance Management page, select Delete Instance, click Next, and DBCA displays the List of Cluster Databases page.

5. Select an Oracle RAC database from which to delete an instance. Click Next and DBCA displays the List of Cluster Database Instances page. The List of Cluster Database Instances page shows the instances that are associated with the Oracle RAC database that you selected and the status of each instance.

6. On the List of Cluster Databases page, select the Oracle RAC database from which to delete the instance, as follows:

   1. On the List of Cluster Database Instances page, DBCA displays the instances that are associated with the Oracle RAC database that you selected and the status of each instance. Select the cluster database from which you will delete the instance. Click Finish.

   2. Click OK on the Confirmation dialog to proceed to delete the instance.

   3. Click OK on the next Confirmation dialog to delete the instance and related Optimal Flexible Architecture (OFA) directory structure.

      DBCA displays a progress dialog showing that DBCA is deleting the instance. During this operation, DBCA removes the instance and the instance's Oracle Net configuration.

      Click No and exit DBCA or click Yes to perform another operation. If you click Yes, then DBCA displays the Operations page.

7. Verify that the dropped instance's redo thread has been removed using SQL*Plus to query the V$LOG view from an existing instance. If the redo thread is not disabled, then disable the thread. For example:

   SQL> ALTER DATABASE DISABLE THREAD 2;
   

8. Verify that the instance has been removed from OCR by running the following command, where db_unique_name is the name of the database:

   srvctl config database -db db_unique_name
   

9. If you are deleting more than one node, then repeat these steps to delete the instances from all the nodes that you are going to delete.