Re: MD RAID6 corrupted by Avago 9260-4i controller [SOLVED]

Wolfgang Denk
2016-05-15T19:35:16Z

Dear Andreas,

In message <20160515183128.GA12823@EIS.leimen.priv> you wrote:
> On Sun, May 15, 2016 at 08:25:24PM +0200, Wolfgang Denk wrote:
> > After creating the overlys, the system would automatically start the
> > (incorrect) RAID arrays.
>
> That should be courtesy of udev, see if you have a
>
> /lib/udev/rules.d/64-md-raid-assembly.rules
>
> and if that's the case you can temporarily disable them by
>
> touch /etc/udev/rules.d/64-md-raid-assembly.rules
>
> and (later) re-enable by rm'ing the /etc/ file.

Thanks.

> > Recovering my data was (fortunately) simple:

Unfortunately my luck did not last very long. While copying the first
file system from the recovered array, the system crashed - can't tell
why, when I got to the console it was all black :-(

So I tried to repeat the same procedure, but it does not work any
more: after erasing the superblocks my attempts to assemble the array
now give only:

# mdadm --assemble /dev/md2 --metadata=1.2 $overlays
mdadm: no RAID superblock on /dev/mapper/sda
mdadm: /dev/mapper/sda has no superblock - assembly aborted

[which is what I had initially expected; I have no idea why it worked
once, but not a second time.]

OK, I can recreate the array, but LVM does not recognize it.

You mentioned I had to play around with the offsets - do you have any
idea which values would be reasonable to try out?

Thanks in advance - once more...

Best regards,

Wolfgang Denk

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