From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaya Potter Subject: recovering from raid5 corruption Date: Sun, 29 Apr 2012 18:38:29 -0400 Message-ID: <4F9DC2E5.1090509@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids somehow my raid5 got corrupted in the contexts of a main disk failure (which wasn't raid related). compounding this issue was that I had already had one disk in the raid5 go bad and was in the process of getting it replaced. this raid array was 5 disks. What I mean by corrupted is that the superblock of 3 of the remaining 4 devices seemed to have been wiped out (i.e. had a UUID of all 0s, though still enough that it knew it was part of an md device) now, the one whose superblock seems fine, places it at position disk 3 (of 0-4) and the missing disk at disk 2. this would imply that there are only 6 permutations possible for the other 3 disks. (even if that assumptions is wrong, there are only 120 permutations possible, which I should easily be able to iterate over). further compounding this, is that there were 2 LVM logical disks on the physical raid device. I've tried being cute and trying all 6 permutations to force recreate the array, but lvm isn't picking up anything. (pvscan/lvscan/lvmdiskscan) The original raid had a version of 0.90.00 (created in 2008), while the new one has a version 1.20. have I ruined any chances of recovery by shooting in the dark with my cute attempts, am I SOL or is there a better/proper way I can try to recover this data? Luckily for me, I've been on a backup binge of late, but there still about 500-1TB of stuff that wasn't backed up. thanks, any help would be appreciated.