It's a good default setting.  Whether or not fragmenting helps you
restore faster depends on a combination of data type and input
pattern, use of multiplexing, and availability of fast locate.

The costs of using fragments of finite size are practically
non-existent.  You wasted a couple of file marks per 2GB image worth
of tape space.  The database gets a tiny bit bigger as it tracks each
fragment (maybe 60B per frag).

The benefit of using fragments is that when it does help, it will
often reduce the tape positioning time during restore from very large
values (measured in hours or portions there of) to a few minutes.

Personally, I see no reason not to use 1-2GB fragments, and possible
huge benefits.

But, be reasonable on the size.  Setting them too small doesn't buy
much (reduce search time from 5 min to 4, for example), and used to
cause extra work during db cleaning.

David A. Chapa writes:
> Did he happen to mention why he thought that?
> 
> <><><><><><><><><><><><><><><><><><><><>
> David A. Chapa
> NetBackup Consultant
> DataStaff, Inc.
> http://www.consulting.datastaff.com
> 847 413 1144
> ---------------------------------------
> NBU-LSERV AT datastaff DOT com - Adv. Scripting
> http://www.xbpadm-commands.com
> 
> -----Original Message-----
> From: veritas-bu-admin AT mailman.eng.auburn DOT edu
> [mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of Cornely,
> David
> Sent: Wednesday, October 17, 2001 8:36 PM
> To: 'Zufall, Ken'; 'rob AT worman DOT org'
> Cc: EBU (E-mail)
> Subject: RE: [Veritas-bu] Fragment size settings
> 
> 
> What I can tell you about fragment size is this:
> The Veritas consultant that just audited our environment said the Fragment
> size for all storage units should be set to 2048.
> 
-- 
Larry Kingery 
      3 kinds of people: those who can count & those who can't.