Automatic Storage Management(ASM) New Features – Oracle Database 20c….

As mentioned in this post, this post is about Automatic Storage Management(ASM) new features in Oracle Database 20c.

File Group Templates

With file group templates you can customize and set default file group properties for automatically created file groups, enabling you to customize file group properties that are inherited by a number of databases.

Without file group templates, if you wanted to change properties for an automatically created file group, you would have to manually change the properties after the associated files are created which triggers an unnecessary rebalance. The file group templates feature provides a much better option. 

Enhanced Double Parity Protection for Flex and Extended Disk Groups

This feature provides support for double parity protection for write-once files in an Oracle Automatic Storage Management (Oracle ASM) Flex Disk Group.

With this feature you can use double parity protection for write-once files in a Oracle ASM Flex Disk Group. Double parity protection provides greater protection against multiple hardware failures. A previous release of Oracle ASM provided for simple parity protection for write-once files in a Flex Disk Group. Write-once files include files such as database backup sets and archive logs. The benefit of parity protection as compared to conventional mirroring is that it reduces storage overhead, but with a slight increase of risk of data loss after an event involving multiple hardware failures. 

Oracle ASM Flex Disk Group Support for Cloning a PDB in One CDB to a New PDB in a Different CDB

Previously point-in-time database clones could only clone a pluggable database (PDB) in a multitenant container database (CDB) to a new PDB in the same CDB. The latter restriction is removed as part of this feature. Now, you can clone a PDB in a CDB to a new PDB in a different CDB.

This feature enables you to use Oracle ASM cloning for test and development cloning where the cloned PDB must be in a separate CDB.

Enable ASMCA to Configure Flex ASM on an Existing NAS Configuration

This feature enables you to install Oracle Flex ASM on a configuration previously configured on network file storage (NFS). In particular, Oracle ASM Configuration Assistant (ASMCA) can be run in silent mode to configure Oracle ASM after an Oracle Clusterware installation has been performed using network attached storage (NAS) for Oracle Cluster Registry (OCR) and Voting disks.

The business value of this feature is that it provides an easy way for you to transition from NFS storage over to Oracle ASM managed storage. Without this feature, you would have to do a complete fresh installation and move all databases. 


Oracle Automatic Storage Management Cluster File System (Oracle ACFS) automatic shrinking automatically shrinks an Oracle ACFS file system based on policy, providing there is enough free storage in the volume.

The benefit is an optimization in performance and space utilization, ensuring that the data migration and associated locking do not cause delays to the running workloads or timeouts.

Mixed Sector Support

Oracle ACFS mixed sector support enables the Linux primary and accelerator volumes of an Oracle ACFS file system to use a mix of different logical sector sizes, such as 512-bytes and 4096 bytes.

The benefit is flexibility for storage configuration, enabling primary and accelerator volumes to have different logical sector sizes on Linux operating systems.

Replication Unplanned Failover

Oracle ACFS replication failover provides unplanned failover where the standby location assumes the role of the primary in case of failure. When a failure occurs, the standby location pursues contact with the primary and in the absence of a response, the standby assumes the primary role, and on recovery of the former primary, the former primary becomes the new standby.

The benefit is faster recovery in the event of unplanned downtime for Oracle ACFS replication.

Oracle ACFS File Based Snapshots

Oracle Automatic Storage Management Cluster File System (Oracle ACFS) file-based snapshots provide the ability to create snapshots of individual Oracle ACFS files in a space efficient manner on Linux.

The benefit is storage efficiency because you only snapshot specific files, not all files in the file system. Example use cases are for virtual machine (VM) image files and PDB snapshot copies.

Hope that helps.