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re: xfsdump/xfsrestore questions.

To: Austin Gonyou <austin@xxxxxxxxxxxxxxx>, <linux-xfs@xxxxxxxxxxx>
Subject: re: xfsdump/xfsrestore questions.
From: Greg Freemyer <freemyer@xxxxxxxxxxxxxxxxx>
Date: Mon, 20 May 2002 17:04:21 -0400
Organization: The NorcrossGroup
Sender: owner-linux-xfs@xxxxxxxxxxx
I can't talk to xfs tuning but ...

Making a generic comparison between windows and xfsdump is unfair, unless you 
have exactly the same hardware involved.

In general you need to have a feed speed about 3x the tapes max. write speed to 
keep the tape streaming.

IIRC a small dat drive can do about 3.6 GB/hr of compressed data.

If your data is 2:1 compressible, that is 7.2 GB/hr uncompressed.  That sounds 
like what you are getting on the windows box.

To get this, you probably have a disk-drive speed of about 21.6 GB/hr or more 
on the windows box.

What sort of disk-drive speed do you have on the xfs box?  I'm sure you know 
that RAID can drastically improve your disk-speed.

BTW: With really high-end drives like SDLT (39 GB/hr compressed), you basically 
have to design your whole storage system around their required feed rate if you 
want them to be able to stream.

Greg Freemyer
Internet Engineer
Deployment and Integration Specialist
Compaq ASE - Tru64
Compaq Master ASE - SAN Architect
The Norcross Group
www.NorcrossGroup.com


 >>  I dumped about 9gb of data to a DDS3 DAT. It took about 4 hours with
 >>  xfsdump.

 >>  On a windows box, with the same TBU, I can dump the same amount in about
 >>  1.5 hrs. Can anyone suggest what I can do to speed things up a bit?

 >>  HP DDS3 SCSI DAT model: C1537A 

 >>  TIA.

 >>  -- 
 >>  Austin Gonyou
 >>  Systems Architect, CCNA
 >>  Coremetrics, Inc.
 >>  Phone: 512-698-7250
 >>  email: austin@xxxxxxxxxxxxxxx

 >>  "One ought never to turn one's back on a threatened danger and 
 >>  try to run away from it. If you do that, you will double the danger. 
 >>  But if you meet it promptly and without flinching, you will 
 >>  reduce the danger by half."
 >>  Sir Winston Churchill



 >>  -- NextPart --
 >>  Attached File: c:\program
 >>  files\goldmine\MailBox\Attach\gaf\signature(12).asc






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