Deleting Oracle RAC from a Cluster Node

You can delete Oracle RAC from cluster nodes using this procedure.

To remove Oracle RAC from cluster nodes, delete the database instance and Oracle RAC before removing the node from the cluster.

Note:

If there are no database instances on the node you want to delete, then proceed to "Removing Oracle RAC".

Deleting Instances from Oracle RAC Databases

You can use the SRVCTL utility to delete an Oracle RAC database instance.

Deleting Instances from Administrator-Managed Databases

Note:

Before deleting an instance from an Oracle RAC database using SRVCTL to do the following:

If you have services configured, then relocate the services

Modify the services so that each service can run on one of the remaining instances

Ensure that the instance to be removed from an administrator-managed database is neither a preferred nor an available instance of any service

Using Oracle DBCA in Interactive Mode to Delete Instances from Nodes

This procedure explains how to use Oracle DBCA in interactive mode to delete instances from Oracle RAC databases.

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

Start Oracle DBCA.
Start Oracle 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 be running during this step.
On the Oracle DBCA Operations page, select Instance Management and click Next. Oracle DBCA displays the Instance Management page.
On the Oracle DBCA Instance Management page, select the instance to be deleted, select Delete Instance, and click Next.
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, Oracle 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.
2. Click OK on the Confirmation dialog to proceed to delete the instance.
  Oracle DBCA displays a progress dialog showing that Oracle DBCA is deleting the instance. During this operation, Oracle DBCA removes the instance and the instance's Oracle Net configuration.
  
  Click No and exit Oracle DBCA or click Yes to perform another operation. If you click Yes, then Oracle DBCA displays the Operations page.
Verify that the dropped instance's redo thread has been removed by using SQL*Plus on an existing node to query the GV$LOG view. If the redo thread is not disabled, then disable the thread. For example:
```
SQL> ALTER DATABASE DISABLE THREAD 2;
```
Verify that the instance has been removed from OCR by running the following command, where db_unique_name is the database unique name for your Oracle RAC database:
```
$ srvctl config database -db db_unique_name
```
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.

Using Oracle DBCA in Silent Mode to Delete Instances from Nodes

Learn how to use Oracle DBCA in silent mode to delete instances from nodes.

Run the following command, where the variables are the same as those shown in Table: Variables in the Oracle DBCA Silent Mode Syntax for the Oracle DBCA command to remove an instance. Provide a node name only if you are deleting an instance from a node other than the one on where Oracle DBCA is running as shown in the following example where password is the password:

dbca -silent -deleteInstance [-nodeName node_name] -gdbName gdb_name
-instanceName instance_name [-sysDBAUserName sysdba -sysDBAPassword password]

At this point, you have accomplished the following:

Deregistered the selected instance from its associated Oracle Net Services listeners
Deleted the selected database instance from the instance's configured node
Removed the Oracle Net configuration
Deleted the Oracle Flexible Architecture directory structure from the instance's configured node.

Removing Oracle RAC

This procedure removes Oracle RAC from the node that you are deleting from a cluster and updates the inventories on the remaining nodes.

If there is a listener in the Oracle RAC home on the node you are deleting, then you must disable and stop it before deleting the Oracle RAC software. Run the following commands on any node in the cluster, specifying the name of the listener and the name of the node you are deleting:
```
$ srvctl disable listener -l listener_name -n name_of_node_to_delete
$ srvctl stop listener -l listener_name -n name_of_node_to_delete
```
Deinstall the Oracle home-only if the Oracle home is not shared-from the node that you are deleting by running the following command from the Oracle_home \deinstall directory:
```
deinstall -local
```
Caution:

If the Oracle home is shared, then do not run this command because it will remove the shared software. Proceed to the next step instead.

Deleting Nodes from A Cluster

Use this procedure to delete nodes from a cluster.

After you delete the database instance and Oracle RAC, you can delete the node from the cluster. Do this by running scripts on the node that you want to delete to remove Oracle Clusterware. Then run scripts on the remaining nodes to update the node list.