On Tue, 29 May 2012 20:48:42 +0200 Oliver Schinagl <oliverlist@xxxxxxxxxxx> wrote: > On 29-05-12 20:44, Oliver Schinagl wrote: > > <snip> > >>>> You can recover your data by re-creating the array. > >>>> > >>>> mdadm -C /dev/md2 -l10 -n2 --layout o2 --assume-clean \ > >>>> -e 1.2 /dev/sda6 /dev/sdb6 > >>>> > >>>> Check that I have that right - don't just assume :-) > >>> That looks very similar to what I used to create the array with, except > >>> the assume-clean part. I wonder however, would it not wiser to create > >>> the array using /dev/sda6 missing thus creating a degraded array? > >>> Atleast I'll still have the sdb6 which MAY contain the data also (since > >>> only sda6 'apparently' has wrong state? > >> That would be a suitable approach - arguably safer. If you feel more > >> comfortable with it, then that is a strong reason to follow that course. > > > > I have tried that on sda6 but it cannot file a filesystem when trying > > to mount md2. This of course is quite scary. I am now slightly > > doubting if my chunksize is the same as before, 128k. > > > > I've used the following command. > > mdadm -C /dev/md2 -c 128 -l 10 -p o2 --assume-clean -e 1.2 -n 2 > > --name=opt /dev/sda6 missing > > > > Now I could try the same on sdb6 and hope that does work, but slightly > > scared of loosing everything on that partition, it could be possible > > of course that sdb6 is the partition that has everything in the > > 'proper' order? I will try to losetup sdb6 with an offset and see if > > that is mountable. > Also, I forgot to mention, the thing that is really strange, is that the > data offset is somewhere extremely strange. > > Data Offset : 262144 sectors 128MB. > > where sda4 and sdb5 (md0 and 1) both have 2048, which sounds common and > sensible. You'll need to use an older mdadm which uses the 2048 (1MB) offset. The next mdadm (3.3) will have a --data-offset option to make this easier to control. For now you need 3.2.3 or earlier. That should make your filesystem accessible. If it doesn't try a different chunk size. Maybe 64, maybe 512. NeilBrown
Attachment:
signature.asc
Description: PGP signature
