Date: Sun, 13 Jun 2004 22:46:22 -0700 (PDT) From: Doug White <dwhite@gumbysoft.com> To: Paul Mather <paul@gromit.dlib.vt.edu> Cc: freebsd-current@freebsd.org Subject: Re: ATA RAID rebuild not rebuilding Message-ID: <20040613223840.L84464@carver.gumbysoft.com> In-Reply-To: <1087173751.697.70.camel@zappa.Chelsea-Ct.Org> References: <1087173751.697.70.camel@zappa.Chelsea-Ct.Org>
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On Sun, 13 Jun 2004, Paul Mather wrote: > I have a recent 5.2-CURRENT system (last built 9th June, 2004) on which > I thought I'd try a RAID 1 mirror using ATA RAID on the built-in Intel > '82371AB/EB/MB PIIX4/4E/4M IDE Controller.' Note there is no hardware RAID support in this controller, so if the wrong disk fails you may not be able to boot. Its just a generic chipset IDE controller. > In summary, I can build and use an ar0 mirror, but whenever I try to > simulate a failure and reconstruction (via atacontrol detach followed by > an atacontrol attach, as described in section 12.4.3 of the FreeBSD > Handbook) the subsequent "atacontrol rebuild ar0" does nothing (it > returns to the prompt immediately) and the ar0 array is still flagged as > DEGRADED (and the detached/attached drive as DOWN). It appears > impossible to revive the array. It should crank up a rebuild thread that will start reconstructing the failed drive in the background. You can see its status with 'ps ax'. Its been a while since I've done this and I've only done it with Promise controllers, which do support RAID features on boot. I think you may have to add the broken disk back as a spare (using 'atacontrol addspare') then initiate the rebuild. > Also, what is the canonical way to construct an array on a built-in > controller? I have two identical ATA drives: ad1 on ATA channel 0, and > ad2 on ATA channel 1. Assuming these are both unpartitioned/empty, do I > first have to fdisk the individual drives or is it enough to "atacontrol > create RAID1 ad1 ad2" and then "fdisk -BI ar0" and bsdlabel ar0s1? You need to create the RAID container first, so atacontrol, then partition the newly minted ar0. > Where is the ATA RAID metadata stored? How is consistency maintained? > Is there some way of forcing a reconstruction onto a particular drive? The metadata is stored on the disks themselves. > In a verbose boot, the array configuration is output. For some reason, > it is flagged as PROMISE. Shouldn't this be FREEBSD? Might that be > confusing the rebuild process, or is rebuilding done identically both on > FreeBSD ATA RAID and Promise ATA RAID controllers? FreeBSD the Promise metadata format in the absence of anything telling it otherwise. It just happens that you don't have a Promise controller that can understand the metadata. :) Incidentally, don't create stripes (RAID0) using this config and expect to boot off of them, 'cause you won't be able to. You need hardware support to do that. -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org
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