Oracle ACFS is always configured with Oracle ASM storage and interfaces with Oracle ASM storage through a traditional device file. This device file is presented by Oracle ADVM and is constructed using a dynamic volume file. The Oracle ADVM volume device file is created automatically following the creation of an Oracle ADVM volume. An Oracle ACFS file system is then bound to the Oracle ADVM device file during the file system creation.
After an Oracle ACFS is configured and mounted, the file system inherits the Oracle ASM storage management features associated with an Oracle ADVM volume, including dynamic balanced distribution, mirroring and striping, and dynamic resizing.
The Oracle ACFS driver establishes communication with the Oracle ASM instance to receive Oracle ASM status information including Oracle ASM instance and disk group state transitions. However, I/O does not go through Oracle ASM nor through the Oracle ASM proxy, but rather goes directly to the underlying Oracle ASM storage.
For information about Oracle ACFS and Oracle ASM operations, refer to "Oracle ACFS and Dismount or Shutdown Operations".