Re: Upgrade from Ubuntu 10.04 to 12.04 broken raid6.

On 9/30/2012 3:22 PM, Mathias Burén wrote:

On 30 September 2012 20:20, EJ Vincent [off-list ref] wrote:

quoted

On 9/30/2012 6:04 AM, Mikael Abrahamsson wrote:

quoted

On Sun, 30 Sep 2012, EJ wrote:

quoted

Fast forward to now, I've upgraded the system to 12.04 LTS and have lost
access to my array. The array itself is a nine (9) disk raid6 managed by
mdadm.

What version of kernel for 12.04 were you running?

If you didn't upgrade your kernel, you might have been hit by the bug
described in:

<http://neil.brown.name/blog/20120615073245>

Hello,

I'm running the stock version of Ubuntu 12.04.0, using kernel
3.2.0-23-generic.

That link looks interesting-- I'm not sure if I triggered the bug how Mr.
Neil Brown describes it, but I definitely have symptoms on some (not all)
the disks of RAID level "-unknown-" and devices appearing to be spares.

I'm hesitant to re-create the array again (using mdadm) because according to
that blog post, for RAID-6, the order of devices are important, and with
this being a 9 disk array and no record of device order in logs or from my
own memory, I have no idea what the proper order might be.

I do know that 1) I was using metadata version 1.2, 2) the array was not
degraded and subsequently 3) no disks were missing.

Am I over-estimating the importance of the order and should proceed with the
re-creation, or perhaps wait for Neil himself to weigh in the problem?

Thanks for all the responses, much appreciated.

-EJ

--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Can't you just boot off an older Ubuntu USB, install mdadm and scan /
assemble, see the device order?

Hi Mathias,

I'm under the impression that damage to the metadata has already been 
done by 12.04, making a recovery from an older version of Ubuntu 
(10.04), impossible.  Is this line of thinking, flawed?

Thanks,

-EJ
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html