Veritas File System

For other uses, see Veritas (disambiguation).

VERITAS File System

Full name	VERITAS File System
Introduced	1991
Structures
Directory contents	extensible hash
Limits
Max file size	8 EB (263 bytes)
Max filename length	256 bytes
Max volume size	128 ZB (277 bytes)
Features
Forks	yes
Attributes	Extended file attributes
File system permissions	POSIX, ACL
Transparent compression	No
Transparent encryption	No
Supported operating systems	Linux, Solaris, HP-UX, AIX, SINIX, UnixWare

The VERITAS File System, (or VxFS, called JFS and OnlineJFS in HP-UX), is an extent-based file system. It was originally developed by VERITAS Software.^[1] Through an OEM agreement, VxFS is used as the primary filesystem of the HP-UX operating system. With on-line defragmentation and resize support turned on via license, it is known as OnlineJFS.^[2] It is also supported on AIX, Linux, Solaris, OpenSolaris, SINIX/Reliant UNIX, UnixWare and SCO OpenServer.^{[citation needed]} VxFS was originally developed for AT&T's Unix System Laboratories. VxFS is packaged as a part of the Veritas Storage Foundation (which also includes Veritas Volume Manager).

History

According to the vendor, it was the first commercial journaling file system.^[3] That claim can be taken in two ways, i.e., the first implementation of a journaling file system in a commercial context, or the first file system available as an unbundled product.

Dan Koren is cited as one of the original developers of VxFS.^[4] He notes in a mailing list that they "finished release 1.0 one year or so later" after starting development of VxFS under a contract with AT&T in 1990.^[5] Other sources agree that the product was first released in 1991.^[6][7]

As the internet was not widely available in the early 1990s, getting a new file system deployed for Unix like operating systems was more difficult, so the one to two year delay in the release and commercialization of this file system was not unusual.

Version history

The on-disk layout of VxFS is versioned and upgradeable while the file system is mounted. This file system has gone through seven versions.

• Version 2 added support for filesets, dynamic inode allocation and ACLs. Layouts 1-3 stopped being supported in VxFS 4.0.

• Version 4 added support for storage checkpoints and for Veritas Cluster File System. Version 4 was released in VxFS 3.2.1. Layout version 4 is no longer supported under VxFS 5.1 [1].

• Version 5 started support for file systems up to 32 terabytes (2⁴⁵ bytes) in size. Individual files can be up to 2 terabytes in size. Version 5 was introduced in VxFS 3.5 and is no longer supported under VxFS 5.1 [2].

• Version 6 added support for file systems and files up to 8 exabytes (2⁶³ bytes) in size. Version 6 also introduced support for named streams/resource forks, for multiple underlying volumes, and for file change logs. Version 6 was introduced in VxFS 4.0.

• Version 7 extends support for multiple volumes to permit Dynamic Storage Tiering. Dynamic Storage Tiering allows root users to move files among different volumes, allocate files to different volumes at file creation time based on policy, and independently recover volumes, without altering the namespace of the file system. Version 7 was introduced in VxFS 5.0

It is assumed that transparent compression and transparent encryption will be addressed in Version 8 or Version 9.

Parallel access mode

VxFS file system can run in single instance mode or in a parallel access / cluster mode. The parallel mode allows for multiple servers (also known as cluster nodes) to simultaneously access the same file system. When run in this mode, VxFS is referred to as Veritas Cluster File System.

The Cluster File System provides cache coherency and POSIX compliance across nodes, so that data changes are atomically seen by all cluster nodes simultaneously. Because Cluster File System shares the same binaries and same on-disk layout as single instance VxFS, moving between cluster and single instance mode is straightforward.

See also

• Comparison of file systems
• Symantec Operations Readiness Tools (SORT)

References

1. ^ "Incrementally restoring a mass storage device to a prior state". 2005-03-22. http://www.patentstorm.us/patents/6871271.html. Retrieved 2007-11-21. 
2. ^ Donna Yobs (2000-04-10). "Post in the veritas-vx mailing list explaining the differences between JFS and OJFS". Archived from the original on 2008-03-09. http://web.archive.org/web/20080309165600/http://mailman.eng.auburn.edu/pipermail/veritas-vx/2000-April/000163.html. Retrieved 2007-11-21. 
3. ^ "VERITAS Foundation Suite and Foundation Suite HA 3.5". VERITAS. http://ftp.support.veritas.com/pub/support/products/FileSystem_UNIX/253148.pdf. Retrieved 2007-11-21. 
4. ^ "6th International Linux Kongress". 1999-09-09. http://www.linux-kongress.org/1999/abstracts.html. Retrieved 2007-11-21. 
5. ^ Dan Koren (1999-06-01). "Re: XFS and journalling filesystems". LKML.org. http://lkml.org/lkml/1999/6/1/31. Retrieved 2007-11-21. 
6. ^ "Next-Gen File Systems — File under 'futuristic': An overview of the technologies and players — The Heavy Hitters: Veritas". Byte and Switch. 2002-11-14. http://www.byteandswitch.com/document.asp?doc_id=24108&page_number=3. Retrieved 2007-11-21. 
7. ^ "VERITAS Celebrates 15 Years - Next Big Focus: Grid Computing". SYS-CON. 2004-09-14. http://issj.sys-con.com/read/46369.htm. Retrieved 2007-11-21. 

External links

• Veritas File System documentation
• VERITAS Storage Foundation
• VxFS Quick Reference
• VERITAS Cluster File System
• Symantec Operations Readiness Tools (SORT)