Re: Help with data recovery - RAID6 with 2 failed drives and another with broken sectors

["Michał Sawicz" <michal@sawicz.net>]

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On 01.10.2013 01:23, Michał Sawicz wrote:
> So the nightmare came for me - I've a 7x2TB setup under RAID6, and one
> of the drives started showing uncorrectable sectors a few days ago, but
> I didn't yet have time to address that. I had two-disk redundancy, after
> all...
> 
> Soon thereafter the cables / controller spew a slew of errors and the
> array was stopped. A --force --assemble later it was back up, rebuilding
> onto 2 spares - I was left with no redundancy. If only the bad sectors
> drive was one of those two, everything would be fine. Unfortunately
> that's not the case, so I'm now left with an array with read errors. So
> it fails during rebuild due to those.
> 
> What I'd like to do first is to make sure the array rebuilds onto the 6
> healthy drives, regardless of the bad blocks, I can probably recover the
> data (assuming I can find out which files were affected - any
> pointers?), but if the array doesn't rebuild correctly, I'm afraid it's
> gonna get worse, and soon.

OK, so a ddrescue and --zero-superblock later my array is rebuilding
onto one healthy spare. According to ddrescue I only lost some 8kB of
data in more or less one chunk, so after the array is rebuilt my next
task will be finding which file(s) that was.

-- 
Michał (Saviq) Sawicz <michal@sawicz.net>


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