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Asked: 2015-09-01 05:32:19 +0800 CST

recover highly degraded raid array

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I have a Linux RAID6 array (mdadm) composed of 8 disks.

2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid

but when I start a raid rebuild, the rebuild fails because a third disk is showing read errors and get ejected of the array.

It's ok to loose data on the few sectors producing read errors.

(What is | is there any) way to recover the raid array ?

raid

1 Answers

  1. You may be able to use a tool like ddrescue to image that 3rd failed drive to one of the new drives. This should be an exact copy minus the bad blocks. This way it won't get read errors. Then replace that 3rd failed drive with the newly imaged one.

    Assuming none of the bad blocks were critical to the RAID or filesystem then you may be able to then assemble the array in degraded mode and either copy as much data off as possible, or try adding more drives for the rebuild/resync (the latter being more risky IMO).

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