Jeff, 

Way back when, in NBU history, backups were written in a single large
tar-ball. This worked great for backups, but restores were a pain. If you
wanted a 1k file at the very end of a 50 gig tar-ball, you had to read the
entire tar-ball from start to finish to get the 1k file. Thus, depending on
where your file was in the backup, it could take hours to get a single file.


Enter the Fragment. You can now set (in the Storage Unit) the size of each
tar-ball. This way, when the same 1k file written at the end of the backup
job is needed to be restored, the restore will skip across the tar-ball
headers till it gets to the correct tar-ball, and then start reading the tar
file to get your 1k file. 

So, in a nutshell, Fragments were introduced to speed up restores of single
files. 

I typically recommend a 2048 (2 gig) size on a Unix Fragment and a 1024 (1
gig) on an Windows Fragment. YMMV. 

Hope this helps. 

dave

__________
dave high
VERITAS Enterprise Consulting
702.683.7733
 
Unix IS user friendly, it's just VERY picky about who it chooses as friends
 

> -----Original Message-----
> From: Jeff Kennedy [mailto:jlkennedy AT amcc DOT com]
> Sent: Monday, January 28, 2002 7:11 AM
> To: NBU List
> Subject: [Veritas-bu] fragment question
> 
> What is the concept behind fragments in NBU?  I ask because I have a
> single client with 106 fragments and I don't understand why?  The client
> is fairly large (200+GB's) but that seems excessive to me.
> 
> Besides the fact that I don't really understand the purpose of the
> fragment......
> 
> Thanks.
> --
> =====================
> Jeff Kennedy
> Unix Administrator
> AMCC
> jlkennedy AT amcc DOT com
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