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Date:      Thu, 13 Jan 2000 13:30:13 +1300
From:      Joerg Micheel <joerg@cs.waikato.ac.nz>
To:        "Kenneth D. Merry" <ken@kdm.org>
Cc:        freebsd-hardware@freebsd.org
Subject:   Re: hardware
Message-ID:  <20000113133013.L5228@cs.waikato.ac.nz>
In-Reply-To: <20000112170836.B93083@panzer.kdm.org>; from Kenneth D. Merry on Wed, Jan 12, 2000 at 05:08:37PM -0700
References:  <387D0354.63159B8@ddsecurity.com.br> <72218.947717759@verdi.nethelp.no> <20000113124314.I5228@cs.waikato.ac.nz> <20000113125237.J5228@cs.waikato.ac.nz> <20000112170836.B93083@panzer.kdm.org>

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On Wed, Jan 12, 2000 at 05:08:37PM -0700, Kenneth D. Merry wrote:
> On Thu, Jan 13, 2000 at 12:52:37 +1300, Joerg Micheel wrote:
> > Regarding the Barracuda ST150176LW ...
> > 
> > I'd like to comment that the real problem with this drive is rather on
> > the backup side. I'm using a DDS4 drive (40GB compressed, 20GB raw) and
> > I get about 10GB / hour backup performance. Both the disk and the tape
> > drive are on the same SCSI channel. The disk is almost full, lots of
> > gzip'ed data on it. It took me an estimated 8 hours and 3 DDS4 tapes for
> > the complete dump 0.
> 
> dump is notoriously slow.  I've got a number of systems that back up onto a
> central AIT drive at work.  We're pushing close to 50G per night onto one
> AIT tape (maximum we've gotten is 55GB on a 170m AIT-1 tape), and it takes
> 9.5-10 hours to do the backup.
> 
> The speed isn't limited by the network (switched 100BaseT) or the drive
> (AIT drives can handle a good bit more than the 1.4MB/sec or so we're
> throwing at it.)  The limiting factor is dump.

Hmm, I have seen 1.7MB with this dump.

> If a file-based backup is acceptable, you could probably get a lot better
> performance by going through the filesystem.

Interesting thought, will try.

> > Time for LTO to show up.
> 
> What's LTO?

Linear Tape Open, looks like pretty accepted technology:

	http://www.lto-technology.com/

Or search on the HP website for Ultrium.

	Joerg
-- 
Joerg B. Micheel			Email: <joerg@cs.waikato.ac.nz>
Waikato Applied Network Dynamics 	Phone: +64 7 8384794
The University of Waikato, CompScience	Fax:   +64 7 8384155
Private Bag 3105			Pager: +64 868 38222
Hamilton, New Zealand			Plan:  TINE and the DAG's


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