Project: OCFS2
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Project Description: General-purpose cluster file system
License: GPL

WHAT IS OCFS2?

OCFS2 is a POSIX-compliant shared-disk cluster file system for Linux capable of providing both high performance and high availability.

As it provides local file system semantics, it can be used with any application. Cluster-aware applications can make use of parallel I/O for higher performance. Applications, not able to benefit from parallel I/O, can take advantage of the file system to provide a fail-over setup to increase its availability.

Apart from being used with Oracle's Real Application Cluster database product, OCFS2 is currently in use to provide scalable web-servers and file-servers as well as fail-over mail-servers and for hosting virtual machine images.

Some of the notable features of the file system are:

  • Variable Block sizes
  • Flexible Allocations (extents, sparse, unwritten extents with the ability to punch holes)
  • Journaling (ordered and writeback data journaling modes)
  • Endian and Architecture Neutral (x86, x86_64, ia64 and ppc64)
  • In-built Clusterstack with a Distributed Lock Manager
  • Support for Buffered, Direct, Asynchronous, Splice and Memory Mapped I/Os
  • Comprehensive Tools support

WHAT'S NEW?

OCFS2 1.4 for EL5 U2+ and SLES10 SP2 has been released.

With this release, there are now two supported releases of the file system, namely, OCFS2 1.2 and OCFS2 1.4.

For Novell's SUSE Linux Enterprise Server, OCFS2 1.2 is bundled with SLES9 SP4 and SLES10 SP1, whereas OCFS2 1.4 is bundled with SLES10 SP2.

For Red Hat's and Oracle's Enterprise Linux, packages for OCFS2 1.2 are available for EL4 U4 onwards and for all current EL5 kernels. Packages for OCFS2 1.4 are available for EL5 U2+. Packages for both OCFS2 1.2 and OCFS2 1.4 will continue to be provided for EL5 kernels.

For Oracle's Unbreakable Linux Network subscribers, OCFS2 1.2 will continue to be the default install. Users wanting to upgrade to OCFS2 1.4 release will need to subscribe to the OCFS2 1.4 packages for Enterprise Linux 5 channel.

OCFS2 1.4 is on-disk compatible with the OCFS2 1.2. The new release can mount volumes formatted and used with the older release, as is. However, as the network protocol is not compatible, concurrent mounts from two nodes running the two different releases is not possible.

To learn more about compatibilities and new features, please refer to OCFS2 1.4 User's Guide.

GETTING STARTED

OCFS2 1.2 users can learn about configuring the file system in OCFS2 1.2 User's Guide. Answers to the commonly asked questions are available in the OCFS2 1.2 FAQ.

OCFS2 1.4 users can learn about the new features, compatibilities, install, configuration and other information in the OCFS2 1.4 User's Guide.

For information regarding migrating data from OCFS to OCFS2, please refer to the OCFS to OCFS2 Migrate Guide. Please note that OCFS refers to the file system that worked on the 2.4 Linux Kernel. Users looking to upgrade from OCFS2 1.2 to OCFS2 1.4 do not have to migrate the data.

OCFS2 1.4 RELEASE

OCFS2 1.4.2-1 and OCFS2 Tools 1.4.2-1 are the latest versions. The list of new features (since OCFS2 1.2) is documented in the OCFS2 1.4 User's Guide.

Oracle's Enterprise Linux: OCFS2 1.4.2-1 packages for EL5 are available on the Unbreakable Linux Network. Users looking to upgrade to this release need to subscribe to the OCFS2 1.4 packages for Enterprise Linux 5 channel. After subscribing, users can upgrade to this release by issuing the following commands: 

	# up2date --install ocfs2-tools ocfs2console
	# up2date --install ocfs2-`uname -r`

Novell's SUSE Linux Exterprise Server: OCFS2 1.4.1-1 packages for SLES10 SP2 are available on download.novell.com. Users looking to use this release must upgrade to SLES10 SP2 and install ocfs2-tools.

Red Hat's Enterprise Linux: OCFS2 1.4.2-1 packages for RHEL5 are available on oss.oracle.com. Users looking to use this release must download and install the appropriate file system and the tools packages.

OCFS2 1.2 RELEASE

OCFS2 1.2.9-1 and OCFS2 Tools 1.2.7-1 are the latest versions. The list of changes since the previous version is documented in the news section for the file system and the tools. Users must upgrade the tools before upgrading the file system.

Oracle's Enterprise Linux: OCFS2 1.2.9-1 packages for EL4 and EL5 are available on the Unbreakable Linux Network. Subscribers can upgrade to the latest version by issuing the following commands: 

	# up2date --install ocfs2-tools ocfs2console
	# up2date --install ocfs2-`uname -r`

Novell's SUSE Linux Exterprise Server: OCFS2 1.2.9-1 packages for SLES9 SP4 and SLES10 SP1 are available on download.novell.com.

Red Hat's Enterprise Linux: OCFS2 1.2.9-1 packages for RHEL4 and RHEL5 are available on oss.oracle.com. Users looking to use this release must download and install the appropriate file system and the tools packages.

SUPPORT

Oracle provides full support for the OCFS2 file system for Oracle's Unbreakable Linux Network subscribers.

Oracle also extends support for the OCFS2 file system to Red Hat Enterprise Linux users for use with Oracle's database product.

Novell provides full support for the OCFS2 file system to SUSE Linux Enterprise Server users.

CERTIFICATION

For the latest information on certification of the OCFS2 file system with various Oracle products, please click on Certify & Availability on metalink.

SOURCE CODE AND LICENCING

The file system source code is available with the mainline Linux kernel that can be downloaded from kernel.org. The file system source code for the Enterprise kernels is available from oss.oracle.com.

The source code for the OCFS2 file system and its tools is available under the GNU General Public License (GPL), version 2.

REPORTING BUGS

Use the bugzilla to file bugs.

Try to be as verbose as possible in the bug reports.

TOP REPORTED ISSUES

Q. If one uses a private ip address, what node name must one specify in cluster.conf?
A. The node name must always be the hostname irrespective of the ip address used. For more, refer to the Configure section in the FAQ.

Q. What should one set O2CB_HEARTBEAT_THRESHOLD to?
A. O2CB_HEARTBEAT_THRESHOLD should be set depending upon the default io timeout for the io layer. For multipath users, set it to a number ranging from 31 to 61. For more, refer to the Heartbeat and Timeouts sections in the FAQ.

Q. How can one avoid a node from panic-ing when one shutdowns the other node in a 2-node cluster?
A. Ensure the ocfs2 init script is enabled. This script ensures that the OCFS2 volumes are umounted before the network is shutdown. For more, refer to the Quorum and Fencing section in the FAQ.

Q. Why does CRS not startup when the Voting diskfile and/or the OCR file are on a OCFS2 volume?
A. OCFS2 volumes containing the Voting diskfile (CRS), Cluster registry (OCR), Data files, Redo logs, Archive logs and Control files must be mounted with the datavolume,nointr mount options. For more, refer to the Oracle RAC section in the FAQ.

MAILING LISTS

To learn about new releases and discuss OCFS2 related issues, please join one or more of the OCFS2 mailing lists.