From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aaron C. de Bruyn" Subject: Re: Moron Destroyed RAID6 Array Superblocks Date: Fri, 13 Apr 2007 23:42:03 -0700 Message-ID: <1176532924.7325.12.camel@localhost.localdomain> References: <200704081521.l38FLwGU017164@cichlid.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200704081521.l38FLwGU017164@cichlid.com> Sender: linux-raid-owner@vger.kernel.org To: Andrew Burgess Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids If the array consisted of 7 drives, two of them would be parity and I'd need to leave them out of the array in order to avoid resyncing. Would I need to specify them as 'missing' so the drives are in the correct order? For example mdadm --raid-devices=7 --level=6 --foo /dev/md0 /dev/sda1 /dev/sdc1 missing /dev/sdb1 /dev/sdg1 missing /dev/sdh1 Or alternatively with the --assume-clean switch, should I specify all 7 drives and see if it mounts? -A On Sun, 2007-04-08 at 08:21 -0700, Andrew Burgess wrote: > >After reading through the linux-raid archives I have been lead to > >believe that I can recover my array by doing a --create and listing the > >7 drives in the exact order I originally created them in. Is this correct? > > >If so, the kernel upgrade managed to shuffle the drive names around...is > >there any way I can figure out what order they should be in? > > If you know the old order just boot the old kernel and recreate there > > If you are using kernel rpms, you always want to 'install' new kernels > and not 'upgrade', that keeps both the old and new kernel available. > > Otherwise, if you pick just 5 for the 7 drives from a raid 6 array > it seems to me you have 5 factorial combinations = 120. You could write > a script that tries them all and then tests by trying a read-only mount? > > Good luck. I mashed a 3.5 TB array once by rerunning the lvm > creation which zeros the first chunk of the resulting device. I was > used to mdadm not hurting user data when creating. Grrr. > > BTW when you test recreate the array make sure you dont start syncing, thats > another reason to just use 5 drives. > > HTH > > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html