Date: Wed, 11 Sep 2002 09:53:47 +1000 From: Tony Landells <ahl@austclear.com.au> To: "Jack L. Stone" <jackstone@sage-one.net> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: DD copy is too slow Message-ID: <200209102353.JAA26605@tungsten.austclear.com.au> In-Reply-To: Message from "Jack L. Stone" <jackstone@sage-one.net> of "Tue, 10 Sep 2002 18:37:31 EST." <3.0.5.32.20020910183731.00fbeac8@mail.sage-one.net>
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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 -- Tony Landells <ahl@austclear.com.au> Principal Networks, Security & IT Systems Engineer Ph: +61 3 9677 9319 Australian Clearing Services Pty Ltd Fax: +61 3 9677 9355 Level 4, Rialto North Tower 525 Collins Street Melbourne VIC 3000 Australia To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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