OCFS2

The Oracle Cluster File System (OCFS, in its second version OCFS2) is a shared disk file system developed by Oracle Corporation and released under the GNU General Public License. The first version of OCFS was developed with the main focus to accommodate Oracle's database management system that used cluster computing. Because of that it was not a POSIX-compliant file system. With version 2 the POSIX features were included.

OCFS2

Developer(s)	Oracle Corporation
Full name	Oracle Cluster file System
Introduced	March 2006 with Linux 2.6.16
Limits
Max volume size	4 PB (OCFS2)[1]
Max file size	4 PB (OCFS2)[1]
Max filename length	255 bytes
Allowed filename characters	All bytes except NUL and '/'
Features
Dates recorded	modification (mtime), attribute modification (ctime), access (atime)
File system permissions	Unix permissions, ACLs and arbitrary security attributes (Linux 2.6 and later)
Transparent compression	No
Transparent encryption	No
Data deduplication	No
Copy-on-write	Yes
Other
Supported operating systems	Linux

OCFS2 (version 2) was integrated into the version 2.6.16 of Linux kernel. Initially, it was marked as "experimental" (Alpha-test) code. This restriction was removed in Linux version 2.6.19. With kernel version 2.6.29 in late 2008, more features were included into ocfs2, such as access control lists and quotas.^[2][3]

OCFS2 used a distributed lock manager which resembles the OpenVMS DLM but is much simpler.^[4] Oracle announced version 1.6 in November 2010 which included a copy on write feature called reflink.^[5]

See also

• Free and open-source software portal

• GlusterFS
• GFS2
• General Parallel File System (GPFS)
• List of file systems
• Lustre (file system)
• MooseFS
• QFS