Project: OCFS2

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

WHAT IS OCFS2?

OCFS2 is a general-purpose 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 almost all applications. Cluster-aware applications can make use of cache-coherent parallel I/Os from multiple nodes to scale out applications easily. Other applications can make use of the file system facilities to fail-over running application in the event of a node failure.

The file system is currently being used in virtualization (Oracle VM) in both the management domain, to host virtual machine images, and in the guest domain, to allow Linux guests to share a file system. It is also being used in database clusters (Oracle RAC), middleware clusters (Oracle E-Business Suite), appliances (SAP's Business Intelligence Accelerator), etc.

Some of the notable features of the file system are:

  • Optimized Allocations (extents, reservations, sparse, unwritten extents, punch holes)
  • REFLINKs (inode-based writeable snapshots)
  • Indexed Directories
  • Metadata Checksums
  • Extended Attributes (unlimited number of attributes per inode)
  • Advanced Security (POSIX ACLs and SELinux)
  • User and Group Quotas
  • Variable Block and Cluster sizes
  • Journaling (Ordered and Writeback data journaling modes)
  • Endian and Architecture Neutral (x86, x86_64, ia64 and ppc64)
  • Buffered, Direct, Asynchronous, Splice and Memory Mapped I/Os
  • In-built Clusterstack with a Distributed Lock Manager
  • Cluster-aware Tools (mkfs, fsck, tunefs, etc.)

WHAT'S NEW?

OCFS2 1.6 is now available with the Oracle Linux 5. It is bundled with Oracle's Unbreakable Enterprise Kernel.

With this release, there are three supported releases of the file system, viz., OCFS2 1.2, OCFS2 1.4 and OCFS2 1.6.

OCFS2 1.2 is available with Oracle Linux 4, OCFS2 1.4 with Oracle Linux 5 (Default Kernel), and OCFS2 1.6 with Oracle Linux 5 (Unbreakable Enterprise Kernel).

OCFS2 1.6 is fully compatible with OCFS2 1.4. Users can upgrade the cluster to the new release one-node-at-a-time (rolling upgrade).


GETTING STARTED

OCFS2 1.6 users can learn about the features, compatibilities, install, configuration and other information in the OCFS2 1.6 User's Guide.

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

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.

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 or OCFS2 1.6 do not have to migrate the data.


OCFS2 1.6 RELEASE

OCFS2 1.6.3-1 and OCFS2 Tools 1.6.3-1 are the latest versions. The new features available in this release include Extended Attributes, POSIX ACLs, REFLINKs, Indexed Directories, Allocation Reservation, Metadata Checksums and User/Group Quotas.

OCFS2 1.6 is only available with the Unbreakable Enterprise Kernel. Users wishing to upgrade to the new release must logon to the Unbreakable Linux Network (ULN) and subscribe to the Oracle Linux 5 Latest channel.

	# up2date kernel
	# up2date oracle-linux
	# up2date ocfs2-tools ocfs2console

OCFS2 1.4 RELEASE

OCFS2 1.4.7-1 and OCFS2 Tools 1.4.4-1 are the latest versions. The list of changes since the previous version is documented in the news sections ( file system, tools).

Oracle Linux: OCFS2 1.4.7-1 packages for OL5 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 1.4 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 1.4.7-1 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 sections ( file system, tools). Users must upgrade the tools before upgrading the file system.

Oracle Linux: OCFS2 1.2.9-1 packages for OL4 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 customers with a subscription for Oracle Linux Basic or Oracle Linux Premier support. For additional details, please refer to Doc ID 1129890.1 on My Oracle Support titled Support and Software Update Policy for OCFS2 Running on Oracle Linux.

Oracle also extends support for the OCFS2 file system to Red Hat Enterprise Linux users for use only with Oracle's database product. This support is limited to OCFS2 versions 1.2 and 1.4. Later versions are not available for RHEL. For additional details, please refer to Doc ID 1253272.1 on My Oracle Support titled Oracle Cluster File System (OCFS2) Software Support and Update Policy for Red Hat Enterprise Linux Supported by Red Hat.

For OCFS2 support on Novell's SUSE Linux Exterprise Server, please check with SUSE.


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,noatime 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.