As Published In Special Edition for Linux 2006

Linux Community Endorses OCFS R2
By Rich Schwerin

Oracle Cluster File System now freely distributed with mainline Linux kernel.

After a lengthy adoption process, the Oracle Cluster File System Release 2 (OCFS Release 2) has been accepted into the mainline Linux kernel. As the first cluster file system to be distributed with the Linux kernel, OCFS Release 2 provides users with an open source alternative to proprietary cluster file systems.

"[Oracle Cluster File System Release 2] is a vital contribution to the open source community," says Andrew Morton, whose work as Linux 2.6 kernel maintainer is sponsored by the Open Source Development Lab. "The endorsement of OCFS Release 2 by the Linux community represents a significant milestone for Oracle."

By distributing OCFS Release 2 through the mainline Linux kernel and major Linux distributors, such as Novell, Oracle reaffirms its commitment to sharing technology that benefits the larger Linux community. OCFS Release 2 is included in the mainline Linux kernel 2.6.16 and is already supported on the SUSE Linux Enterprise platform from Novell.

User Benefits

OCFS Release 2 is a general-purpose shared disk cluster file system for Linux, which means that it arbitrates access to a shared disk to present a unified view of file and directory contents across cluster nodes, explains Mark Fasheh, Oracle senior software developer and maintainer of OCFS Release 2.

"OCFS Release 2 enables customers to use a file system on their shared disk so they can do things like a shared ORACLE_HOME installation, and share logfiles and datafiles," says Fasheh. "Thanks to direct I/O support, our datafile performance is on par with raw disk. So overall users get a lot of convenience because they can use their normal file system utilities in an OCFS Release 2 cluster."

Designed to work as a seamless addition to the Linux kernel, OCFS Release 2 significantly eases system management while improving performance. It enables all nodes in a cluster to concurrently access a given file system, allowing for simplified management of databases that are shared across a cluster.

OCFS was originally released in December 2002 and allowed Oracle Real Application Clusters customers to run clustered databases without the complexity of raw devices. OCFS Release 2 was developed to provide full functionality as a cluster file system, one which would support more than just Oracle-specific files; it continues to provide the same RAW-equivalent file system performance and is certified to run in instances where OCFS Release 1 was used previously.

Fasheh notes several new features in OCFS Release 2, including accelerated metadata performance, improved data caching and locking for regular files such as Oracle binaries and libraries, and improved journaling and node recovery using the standard Linux Kernel JBD (journaling block device) subsystem. In addition, OCFS Release 2 allows node-local and architecture-local files using Context Dependent Symbolic Links, so the same file can have the same or different content on each node, thus allowing different configurations per node.

Next Steps LEARN more about Cluster File System Release 2 READ Oracle Cluster File System (OCFS2) User's Guide DOWNLOAD OCFS Release 2

Rigorous Process

The kernel adoption process, says Fasheh, was extremely rigorous. "The kernel community has very high standards for inclusion, and rightfully so. It involved several months of public code review, during which we had to make many changes to the file system code," explains Fasheh. "It's a great system because everyone wins. In the end we had a better file system, and the kernel community had something that was easier to maintain and a file system they could 100 percent stand behind."

So what's in store for OCFS? Continued maintenance to address user issues, greater performance, and new features, promises Fasheh. "A general-purpose cluster file system is a huge project, so we're always looking at what's going on in the file system world. Most important, we're looking to our customers for inspiration."