From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Landman Subject: Re: RAID 5 Recovery Help Needed Date: Fri, 16 Jan 2009 15:42:59 -0500 Message-ID: <4970F153.30106@scalableinformatics.com> References: <4970E18C.2000100@mike01.com> Reply-To: landman@scalableinformatics.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4970E18C.2000100@mike01.com> Sender: linux-raid-owner@vger.kernel.org To: Mike Berger Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Mike Berger wrote: > Created the array: > # mdadm --create --verbose /dev/md0 --level=5 --chunk=128 > --raid-devices=3 /dev/sdb1 /dev/sdc1 /dev/sdd1 eek ... a RAID5 on 3 drives? Did you do an mdadm --detail --scan > /etc/mdadm.conf after this? [...] > At this point I used the newly created array for a few days without any > issues at all. ... but did you update mdadm.conf as above? [...] > Now I tried to assemble the array manually using the following commands, > all of which failed (note that I had never edited mdadm.conf). > > # mdadm --assemble --scan This generally requires an /etc/mdadm.conf (or similar /etc/mdadm/mdadm.conf) > # mdadm --assemble --scan --uuid=3128da32:c5e4ff31:b43fc0e6:226924cf > # mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1 > # mdadm --assemble -f /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1 > # mdadm --assemble --uuid=3128da32:c5e4ff31:b43fc0e6:226924cf /dev/md0 > /dev/sdb1 /dev/sdc1 /dev/sdd1 You can often (re)construct this file if you forget to create it with a little detective work ... mdadm --examine /dev/sdb1 could be your friend. [...] > # fsck.ext4 -n /dev/md0 > > I get: > > fsck.ext4: Superblock invalid, trying backup blocks... > fsck.ext4: Bad magic number in super-block while trying to open /dev/md0 > > I've tried specifying the blocksize and specifying the superblock > manually using the backup superblocks from when I ran mkfs.ext4, but > get the same result. I haven't dared to run fsck without -n until I > hear from someone more knowledged. > > So, if anyone has any suggestions on how I can get md0 mounted or > recover my data it would be much appreciated. I am not completely sure, but I would bet that with the changes you have made, that this data may not be recoverable at this point. Before you do anything else, I would definitely suggest creating the mdadm.conf file properly as noted above. Joe -- Joe Landman Scalable Informatics LLC, email: landman@scalableinformatics.com web : http://www.scalableinformatics.com