OCFS2 란 무엇인가??

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.)