Subject: Veritas File System
To: None <tech-kern@NetBSD.ORG>
From: Victor Escobar -- DirectX 5.0 Beta Tester <>
List: tech-userlevel
Date: 07/05/1997 17:17:11
I don't know exactly where file system issues fall, or whether there
is a separate mailing list, but here goes.  I was perusing an ancient
(Feb 95) issue of BYTE magazine and noticed a very interesting article
on a robust file system called Veritas (vxfs).  It has the following
advantages over ffs and its BSD derivatives:

* a Volume Manager accessible via either graphical, text-menu or
command line modes.  Each physical disk is divided into _subdisks_
(unmanaged blocks of disk sectors).  You can combine one or more of
these into a _plex_ to store live data.  A sysadmin is able to span
these, shrink them, expand them, all while the system is up and
running.  This is transparent to users.

* the _intent log_ (vxfs is a journalling file system) is a circular
buffer that logs all pending changes to the fs.  In the event of a
power failure, a modified fsck merely looks in the log and rolls back
and performs the pending operations, as opposed to examining disparate
structures all over the drive.

* the _snapshot_ provides a valuable backup/restore resource.  A
read-only file system is created, which duplicates the live file
system on the main volumes.  A deleted file is first copied to the
snapshot system before being deleted from the real fs and the space
reallocated.  This provides a space-conserving way to have some

I apologise for the rather superficial and sparse info in this email
(can't be responsible for BYTE's editorial slant) but here are some
URL's for more info on vxfs:

Please also cc: any posts re: this to and
let me know any thoughts.  Keep in mind that I'm a complete *BSD
novice, so go easy on me. ;-)

Victor Escobar        |
Internet Consultant   |