Jason, thats exactly what I think
and thats how ASM (STK product) does its backups.
Unless we clarify it alot of people here
may change a setting they otherwise would not
and should not. Thats why I raised my point to
begin with.

Regards
Peter Marelas

-----Original Message-----
From: Jason Ahrens [mailto:jason.ahrens AT telus DOT com]
Sent: Friday, 19 October 2001 2:28 AM
To: Veritas-bu AT mailman.eng.auburn DOT edu
Subject: RE: [Veritas-bu] Fragment size settings



On Fri, 19 Oct 2001, Marelas, Peter wrote:

> Hmm. If thats the case Im very surprised since
> Ive never heard anyone complain about Netbackup taking
> a very long time to restore a file.
>
> The fragment size by default is 0 which I believe
> means unlimited. Based on my logic, unlimited is bound
> to EOT.
>
> If it turns out to be true I think the default is
> a very bad choice.
>
> My -guess- is fragment size is more geared towards disk
> storage units.
>
> If I get time to test it I will post a conclusion.

I may be way off base here, but I think NetBackup also stores the file
offset within the tar file. Most drives will allow seeking to a particular
offset on the tape and, if the program supports it somehow, you can read
directly out of the middle of the archive. I would not be surprised if
this is what NetBackup does.

We have our fragment size set to 0 and have never had to wait more than
about a minute for NetBackup to find what it is looking for for a restore,
regardless of where on the tape the data is stored.

However if I ever needed to do a restore using tar from the command line,
smaller fragments would definitly be a huge bonus.

Jason
--
Jason Ahrens
Systems Administrator/Backup Specialist
PSINet Canada Inc., a TELUS company
http://www.psi.ca
The Future is Friendly

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