What is Oracle ACFS?
Oracle ACFS, as part of Oracle Grid Infrastructure, starting from 12c release 1 this known as Oracle Cloud File System, is integrated with Oracle ASM, Oracle ADVM and Oracle Clusterware as shown in diagram below.
ACFS communicates with Oracle ASM to obtain ASM disk group storage addresses and uses these addresses to read and write ACFS data directly onto ASM storage for maximum performance. It also communicates with Oracle Clusterware to facilitate resource management for ACFS.
All ACFS I/O requests are transferred directly to ASM disk group storage as shown in the diagram. ACFS IO does not pass through the Oracle ASM instance.
The more important advantages of ACFS is ACFS snapshot. It is a point in time copy of file system, which can be read-only, read-write, space-efficient, and it is available immediately to users for testing.
From 12c ACFS supports to create a database (database version 11.2.0.4 and up), Snaps-of-Snaps a new snapshot from an existing snapshot which will allow us to duplicate or create another database very quickly.
ACFS also allows other features like security, replication, encryption, tagging, compression, auditing, etc. Oracle ACFS Snapshots may serve as point-in-time backups of the database that to use for online recovery while having its files stored on Oracle Cloud file system.
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