New features in Oracle Clusterware 12c

1. Oracle Flex ASM - This feature of Oracle Clusterware 12c claims to reduce per-node overhead of using ASM instance. Now the instances can use remote node ASM for any planned/unplanned downtime. ASM metadata requests can be converted by non-local instance of ASM.

2. ASM Disk Scrubbing - From RAC 12c, ASM comes with disk scrubbing feature so that logical corruptions can be discovered. Also Oracle 12c ASM can automatically correct this in normal or high redundancy diskgroups.

3. Oracle ASM Disk Resync & Rebalance enhancements.

4. Application Continuity (AC) - is transparent to the application and in-case the database or the infrastructure is unavailable, this new features which work on JDBC drivers, masks recoverable outages. This recovers database session beneath the application so that the outage actually appears to be delayed connectivity or execution. Transaction guard (improvements of Fast Application Notification).

5. IPv6 Support - Oracle RAC 12c now supports IPv6 for Client connectivity, Interconnect is still on IPv4.

6. Per Subnet multiple SCAN - RAC 12c, per-Subnet multiple SCAN can be configured per cluster.

7. Each RAC instance opens the Container Database (CDB) as a whole so that versions would be same for CDB as well as for all of the Pluggable Databases (PDBs). PDBs are also fully compatible with RAC.

8. Oracle installer will run root.sh script across nodes. We don't have to run the scripts manually on all RAC nodes. 

9. New "ghctl" command for patching.

10. TAF is extended to DML transactions failover (insert/update/delete).

10. TAF is extended to DML transactions failover (insert/update/delete).