Converting an Oracle 12c Clusterware Standard Cluster to an Oracle Flex Cluster

The following is a summarized procedure in how to convert from Oracle 12c standard Cluster to Oracle New Flex cluster.


  1. Execute the following command to check your current cluster mode:

crsctl get cluster mode status

    cluster is running in “standard” mode

  1. Run the command to check that GNS is configured with fixed IP:

srvctl config gns

** if GNS  is not configured then you need to do so by executing the following command as “root” after making sure that GNS IP entry is added in DNS server:

srvctl add gns -vip vipname | ip_address

                 srvctl start gns


  1. Set the mode of the cluster to “flex” by executing the below command as “root”:

crsctl set cluster mode flex

Cluster mode set to “flex”


  1. Stop/Start the cluster so the new mode takes affect:

 crsctl stop crs

                   crsctl start crs

Status of cluster mode is “FLEX”


Important Final Remarks:

  • The cluster conversion is one direction from standard===> Flex  ONLY.


  • GNS is required with fixed IP address for Flex setup.


  • Oracle Flex cluster works ONLY with Oracle Flex ASM, while Oracle Flex ASM can work with either standard or Flex cluster.


                   Oracle Flex Cluster Architecture





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