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Date:      Tue, 10 Sep 2002 19:21:52 -0500
From:      "Jack L. Stone" <jackstone@sage-one.net>
To:        Tony Landells <ahl@austclear.com.au>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: DD copy is too slow 
Message-ID:  <3.0.5.32.20020910192152.00fbeac8@mail.sage-one.net>
In-Reply-To: <200209102353.JAA26605@tungsten.austclear.com.au>
References:  <Message from "Jack L. Stone" <jackstone@sage-one.net> <3.0.5.32.20020910183731.00fbeac8@mail.sage-one.net>

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At 09:53 AM 9.11.2002 +1000, Tony Landells wrote:
>What kind of disks are involved?
>
>I was having a similar problem recently and went hunting on the
>Maxtor web site, where I discovered an interesting little tech
>support note that Maxtor disks are shipped with a "feature" that
>verifies all writes until the power has been cycled 10 times.
>
>They also have a DOS utility that can turn it on, turn it off,
>change the counter value, ...
>
>So out of curiosity I found a DOS boot disk, put the utility on
>it, and rebooted the machine to check the status of the write
>verify.  It came up and said write verification was disabled.
>
>When I rebooted back to FreeBSD the problem was fixed.
>
>While it is possible that the reboot I did to run the DOS utility
>was the 10th reboot that caused the write verify feature to be
>disabled, I don't think so.  I had already been doing disk-to-disk
>tests and getting decent throughput.  It seemed to be more some
>bizarre anomaly that arose in the box when we moved it to the
>install site, and somehow the couple of reboots we did fixed it.
>
>Also, the Maxtor disk came in a HP PC with Windows 2000 pre-installed.
>Presumably there were at least a couple of reboots involved in HP
>installation process, and presumably some sort of QA.  Then the PC
>had been rebooted here at least a few times.  It may not have been
>far beyond 10 reboots, but I think it's likely it was beyond it.
>
>However, that doesn't mean that other people aren't getting bitten
>by it, particularly if you buy a "clean" Maxtor disk and drop it
>in your FreeBSD box.
>
>Either way, my suggestion is reboot the box once or twice and see
>if it fixes it (as it did for me), and if not and it's a Maxtor
>disk you're trying to write to, download their utility, put it on
>a DOS boot disk and make sure the write verify flag is off.
>
>Tony
>-- 

Thanks, Tony... these are Seagate 40GB and ad0 and ad1 were previously used
in a RAID-1 array for a short time. I disabled the RAID & added ad2 to use
3 40GB identical HDs on this box as a "build" box and as a backup server.
The ones used for RAID HDs have been in service a few months and ad2 is
brand new.

Obviously, something needs a tweak....

Best regards,
Jack L. Stone,
Administrator

SageOne Net
http://www.sage-one.net
jackstone@sage-one.net

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