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Developer(s) Oracle Corporation
Full name Oracle Cluster file System
Introduced March 2006 with Linux 2.6.16
Max. volume size 4 PB (OCFS2)[1]
Max. file size 4 PB (OCFS2)[1]
Max. filename length 255 bytes
Allowed characters in filenames All bytes except NUL and '/'
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
Supported operating systems Linux

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 (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]

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Notes and references[edit]

  1. ^ a b Limited to 16TiB since it uses the Linux JBD
  2. ^ Mark Fasheh (December 19, 2008). "Ocfs2 patches for merge window batch 1/3". Linux Kernel Mailing List. Retrieved October 24, 2016. 
  3. ^ Mark Fasheh (December 22, 2008). "Ocfs2 patches for merge window batch 2/3". Linux Kernel Mailing List. Retrieved October 24, 2016. 
  4. ^ Jonathan Corbet (May 24, 2005). "The OCFS2 filesystem". LWN.net. Retrieved October 24, 2016. 
  5. ^ John Margaglione (November 30, 2010). "What's new in Oracle Linux Part 1: OCFS2 1.6 REFLINKs". Oracle. Retrieved October 24, 2016. 

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