On Sun, 29 Apr 2012 18:38:29 -0400 Shaya Potter <spotter@xxxxxxxxx> wrote: > 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. You've written a new superblock 4K in to each device, where previously here was something. So you have probably corrupted something though we cannot easily tell what. Retry your experiment with --metadata=0.90. Hopefully one of those combinations will work better. If it does, make a backup of the data you want to keep, then I would suggest rebuilding the array from scratch. NeilBrown
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