Steps to change the standard Oracle Clusterware to Flex Cluster.

Following are the general steps to change the default Oracle Clusterware to Flex cluster configuration:

1. Check the current mode of the cluster

crsctl get cluster mode status


2. Check grid naming service is configured with fixed VIP.

srvctl config gns


3. If there is no GNS then create one with root user otherwise skip this step.

-- Add gns with fixed VIP
srvctl add gns -vip vip_name | ip_address

-- Start the gns service
srvctl start gns


4. Open the ASMCA utility to enable the Oracle Flex ASM in cluster.

5. Change the mode of cluster to flex with root user.

crsctl set cluster mode flex


6. Stop Oracle Clusterware with root user.

crsctl stop crs


7. Start Oracle Clusterware with root user.

crsctl start crs -wait

Note: -wait: display progress and status messages.

8. Add a Leaf listener.

srvctl add listener -leaflistener


For understand the Oracle Flex clusterware go to link: Oracle Flex Cluster