View source for OCFS2

{{Short description|Clustered file system}}
{{Infobox filesystem
| name                    = OCFS2
| full_name               = Oracle Cluster file System
| developer               = [[Oracle Corporation]]
| introduction_os         = [[Linux]] 2.6.16
| introduction_date       = March 2006
| partition_id            =
| directory_struct        =
| file_struct             =
| bad_blocks_struct       =
| max_filename_size       = 255 bytes
| max_files_no            =
| max_volume_size= 4 PB (OCFS2)<ref name="JBD">Limited to 16TiB before 2.6.28 since it used the Linux [[Journaling block device|JBD]]. JBD2 removes the limit.</ref>
| max_file_size= 4 PB (OCFS2)<ref name="JBD"/>
| filename_character_set  = All bytes except [[Null character|NUL]] and '/'
| dates_recorded          = modification (mtime), attribute modification (ctime), access (atime)
| date_range              =
| date_resolution         =
| forks_streams           =
| attributes              =
| file_system_permissions = Unix permissions, [[Access Control List|ACLs]] and arbitrary security attributes (Linux 2.6 and later)
| compression             = No
| encryption              = No
| single_instance_storage = No
| copy_on_write           = Yes
| OS                      = 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)|Linux kernel]]. Initially, it was marked as "experimental" ([[Software release life cycle#Alpha|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 list]]s and quotas.<ref>{{cite web |title= Ocfs2 patches for merge window batch 1/3 |author= Mark Fasheh |date= December 19, 2008 |work= Linux Kernel Mailing List |url= https://lkml.org/lkml/2008/12/19/280 |access-date= October 24, 2016 }}</ref><ref>{{cite web |title= Ocfs2 patches for merge window batch 2/3 |author= Mark Fasheh |date= December 22, 2008 |work= Linux Kernel Mailing List |url= https://lkml.org/lkml/2008/12/22/213 |access-date= October 24, 2016 |archive-date= October 25, 2016 |archive-url= https://web.archive.org/web/20161025110813/https://lkml.org/lkml/2008/12/22/213 |url-status= live }}</ref>

OCFS2 used a [[distributed lock manager]] which resembles the [[OpenVMS]] DLM but is much simpler.<ref>{{cite web |url= https://lwn.net/Articles/137278 |title= The OCFS2 filesystem |work= [[LWN.net]] |author= Jonathan Corbet |date= May 24, 2005 |access-date= October 24, 2016 }}</ref>
Oracle announced version 1.6 in November 2010 which included a [[copy on write]] feature called reflink.<ref>{{Cite web |title= What's new in Oracle Linux Part 1: OCFS2 1.6 REFLINKs |author= John Margaglione |publisher= Oracle |date= November 30, 2010 |url= https://blogs.oracle.com/devpartner/entry/whats_new_in_oracle_linux |archive-url= https://web.archive.org/web/20170510113950/https://blogs.oracle.com/devpartner/entry/whats_new_in_oracle_linux |url-status= dead |archive-date= May 10, 2017 |access-date= May 10, 2017 }}</ref>

==See also==
{{Portal|Free and open-source software}}
* [[GlusterFS]]
* [[GFS2]]
* [[General Parallel File System]] (GPFS)
* [[List of file systems]]
* [[Lustre (file system)]]
* [[Moose File System|MooseFS]]
* [[QFS]]

==Notes and references==
{{Reflist}}

==External links==
*[http://oss.oracle.com/projects/ocfs2/ OCFS2] project page
*[http://oss.oracle.com/projects/ocfs/ OCFS] project page
*{{cite web|url=https://www.kernel.org/doc/Documentation/filesystems/ocfs2.txt|title=OCFS2 filesystem|date=2011-08-11}}

{{Filesystem}}
{{Oracle FOSS}}

{{DEFAULTSORT:Ocfs}}
[[Category:Shared disk file systems]]
[[Category:Oracle software]]
[[Category:Distributed file systems supported by the Linux kernel]]