Date: Tue, 10 Jun 2008 18:09:25 +0300 From: Manolis Kiagias <sonicy@otenet.gr> To: Erik Trulsson <ertr1013@student.uu.se> Cc: freebsd-questions@freebsd.org, DA Forsyth <iwrtech@iwr.ru.ac.za> Subject: Re: xRAID disks.... Message-ID: <484E9925.2050507@otenet.gr> In-Reply-To: <20080610145926.GA66984@owl.midgard.homeip.net> References: <484EACEB.7169.43FE1258@iwrtech.iwr.ru.ac.za> <20080610145926.GA66984@owl.midgard.homeip.net>
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Erik Trulsson wrote: > On Tue, Jun 10, 2008 at 04:33:47PM +0200, DA Forsyth wrote: > >> Hiya >> >> I've had this for a while now and have done many searches for info >> but have not yet come up with the right question, hence have not got >> the answer. >> >> My main server has an Adaptec IDE raid card. A couple of years ago I >> took disks that had been a mirror pair on that card out of the server >> and put them into my test server, not as a raid pair since the test >> server has no raid hardware. >> >> During boot I see this >> ad0: 19092MB <WDC WD200EB-00CPF0 06.04G06> at ata0-master UDMA66 >> ad1: 76319MB <WDC WD800JB-00ETA0 77.07W77> at ata0-slave UDMA66 >> ad2: 76319MB <WDC WD800JB-00ETA0 77.07W77> at ata1-master UDMA66 >> ad3: 19092MB <WDC WD200EB-00CPF0 06.04G06> at ata1-slave UDMA66 >> ar0: 76319MB <Adaptec HostRAID RAID1> status: BROKEN >> ar0: disk0 DOWN no device found for this subdisk >> ar0: disk1 DOWN no device found for this subdisk >> >> The pair of ex-RAID disks are ad1 and ad2 and obviously are no longer >> a raid pair, yet 'something' is telling the ar() driver to try and >> pair them and failing because there is no raid hardware in that box. >> >> Now I am reconfiguring that machine a bit and would like to fix this, >> both on these existing drives and on the 320MB drive I have just >> removed from a RAID1 pair and will be putting into the box instead of >> ad3 (the other 320GB from the pair is in a USB enclosure for other >> purposes and has not shown any signs of knowing it was in a raid >> pair) >> >> I suspect the raidinfo is stored on the disk somewhere and a suitable >> 'dd' command can erase it. but where and how? >> > > That kind of information is usually stored last on the disk (where it is > least likely to be overwritten by filesystems, partitioning info, or boot > loaders), so if you overwrite the last couple of KBs on those disks you will > probably be fine. > (If you want to be certain you can always use 'dd' to nuke all the > information on the disk. That will take longer time, but you get the extra > advantage of testing all the blocks on the disk so that they work > correctly.) > > For the first you could do something like: > dd if=/dev/zero of=/dev/ad1 bs=1m skip=76318 > which should overwrite the last MB of ad1 with zeros. > > To erase all of the disk: > dd if=/dev/zero of=/dev/ad1 bs=1m > > > I recently removed one pair of disks from a windows "hardware :)" RAID controller, and upon inserting it into a newly built FreeBSD system, it was immediately detected by the ar driver, and messages started coming in, like in your case. Although I ended up removing the ar device from the kernel (I was going to use gmirror), I found out that there is possibly another way to make the disks forget about their previous RAID-life: atacontrol delete ar0 Have a look at man atacontrol. I have not tried it, but it is probably worth a try.
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