1 About OCFS2

OCFS2 (Oracle Cluster File System Version 2) is a general-purpose shared-disk file system intended for use with clusters. OCFS2 offers high performance and high availability. You can also mount an OCFS2 volume on a standalone system that's not clustered.

Oracle Cluster File System Version 2 (OCFS2) is available on Unbreakable Enterprise Kernel (UEK) releases only, starting with Unbreakable Enterprise Kernel Release 6 (UEK R6).

Using OCFS2 offers the following benefits:

  • You can use the reflink command with OCFS2 to create copy-on-write clones of individual files. You can also use the cp --reflink command similarly to how you would on a Btrfs file system. Typically, these clones let you save disk space when storing copies of files that are similar, such as virtual machine (VM) images or Linux Containers.

    Note:

    When you use the reflink command, the resulting file system becomes a clone of the original file system, which means that their UUIDs are identical. When creating a clone with the reflink command, you must change the UUID by using the tunefs.ocfs2 command. See Querying and Changing Volume Parameters

  • Mounting a local OCFS2 file system lets you later migrate the file system to a cluster file system without requiring any conversion.

  • OCFS2 provides local file system semantics. Therefore, most applications can use OCFS2. Applications that are cluster-aware can use cache-coherent parallel I/O from many cluster nodes to balance activity across the cluster, or they can use the available file-system functionality to fail over and run on another node if a node fails.