Oracle ACFS ( ASM Cluster File System )

Automatic Storage Management for All Data
These features extend the capabilities of Automatic Storage Management (ASM) to
support all types of data including database files, clusterware files, and file system
data such as Oracle homes and binaries.
1.12.1.1 ASM Cluster File System (ACFS)
The ASM Cluster File System (ACFS), extends Automatic Storage Management (ASM)
by providing a robust, modern, general purpose file system for files beyond the Oracle
database files. ACFS provides support for files such as Oracle binaries, report files,
trace files, alert logs, and other application data files. With the addition of the Oracle
ASM Cluster File System, ASM becomes a complete storage management solution for
both Oracle database and non-database files.
ACFS supports large files with 64-bit file and file system data structure sizes leading to
exabyte-capable file and file system capacities. ACFS scales to hundreds of nodes and
uses extent-based storage allocation for improved performance. A log-based metadata
transaction engine is used for file system integrity and fast recovery. The ACFS on-disk
structure supports endian neutral metadata. ACFS file systems can be exported to
remote clients through industry standard protocols such as NFS and CIFS.
Oracle ASM Cluster File System (ACFS) complements and leverages Automatic
Storage Management (ASM) and provides a general purpose journaling file system for
storing and managing non-Oracle database files. This eliminates the need for
expensive third party cluster file system solutions while streamlining, automating and
simplifying all file type management in a single node as well as Oracle RAC and Grid
computing environments.
ACFS supports dynamic file system expansion and contraction without any
downtime. ACFS is highly available leveraging the ASM mirroring and striping
features in addition to hardware RAID functionality.


Oracle Cluster Registry (OCR) and Voting Disk on ASM
Automatic Storage Management (ASM) disks are used to store the Oracle Cluster
Registry (OCR) and the Voting disks. ASM Partnership and Status Table (PST) is
replicated on multiple disks and is extended to store the OCR. Consequently, the OCR
tolerates loss of the same number of disks as the underlying disk group. OCR is
relocated in response to disk failures.
ASM reserves a number of blocks at a fixed location of every ASM disk for storing the
Voting disk. Should the disk holding the Voting disk fail, ASM selects another disk on
which to store this data.
Storing the OCR and the Voting disk inside on ASM eliminates the need to use
expensive third party cluster volume managers or to deal with the complexity of
managing disk partitions for OCR and Voting disks in Oracle RAC configurations.

 

---------------------------------------------------------------

 

ASM new feature in 11gR2

1. Oracle Cluster Repository (OCR) and Voting Disk stored in ASM
This feature enables ASM to provide a unified storage solution, storing all the data for the clusterware and the database, without the need for third-party volume managers or cluster file systems.

2. Oracle Automatic Storage Management Cluster File System (Oracle ACFS)
Oracle Automatic Storage Management Cluster File System (Oracle ACFS) is a new multi-platform, scalable file system, and storage management design that extends Automatic Storage Management (ASM) technology to support of all your application data in both single host and cluster configurations. Additionally, Oracle ACFS provides snapshot functionality for a point in time copy of an Oracle ACFS system.


3. Oracle Automatic Storage Management Cluster File System Snapshots
An Oracle ACFS Snapshot is a point-in-time copy of a file system that can provide up to 63 snapshot images. Oracle ACFS Snapshot performs fast creation of persistent Oracle ACFS images at a specific point in time with very low overhead leveraging the Copy-on-Write (COW) technology