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re: xfsdump/xfsrestore questions.

To: Greg Freemyer <freemyer@xxxxxxxxxxxxxxxxx>
Subject: re: xfsdump/xfsrestore questions.
From: Austin Gonyou <austin@xxxxxxxxxxxxxxx>
Date: 20 May 2002 16:27:39 -0500
Cc: linux-xfs@xxxxxxxxxxx
In-reply-to: <20020520210943.YYXJ24137.imf24bis.bellsouth.net@taz>
Organization: Coremetrics, Inc.
References: <20020520210943.YYXJ24137.imf24bis.bellsouth.net@taz>
Sender: owner-linux-xfs@xxxxxxxxxxx
On Mon, 2002-05-20 at 16:04, Greg Freemyer wrote:
> 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.
> 
Yes, exactly the same hardware. Only difference in this case is
software.

> 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.
> 
Yes, that can be correct.

> 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.
> 
The issue here is that both jobs are using compression, but Arcserve
2000 on NT is performing faster than say, tar or xfsdump. The problem
I've got with this though, is that it's so much longer there's got to be
something I could tweak, either with xfsdump or the drive, so that's
what prompted my query.

> 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.
10K RPM 18GB Seagate at LVD(80mb/s) (yes..I know about theoretical max,
etc.)
The HP is at 10MB/s, I'd prefer to make it 20MB/s though..at least.(can
set it in the SCSI bios I think?


> 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.
> 
I'm quite aware of that..but thanks for the reminder. :)


> 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
-- 
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

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