Re: Can I replace raid6 disk using dd?

[Killian De Volder <killian.de.volder@megasoft.be>]

No need to remove the bitmap.
But be very careful that the disk is exactly the same size (or bigger).
I recently had a disk that was slightly smaller then advertised !

But if it's a raid6 why not just jank a disk ?
It's still going to be redundant, but only on 1 disk.

Killian De Volder
Megasoft bvba
killian.de.volder@megasoft.be

On 19-08-14 04:49, Ram Ramesh wrote:
> On 08/18/2014 09:30 PM, Ethan Wilson wrote:
>> On 18/08/2014 21:26, Ram Ramesh wrote:
>>> I had a recent disk failure in my 4x2TB raid6 and as a temporary fix I
>>> added a 4tb drive to prevent the drive from being degraded while I
>>> researched for a new drive.
>>>
>>> Now that I have purchased a new drive, I am wondering if it is ok to
>>> simply dd the first 2tb of the 4tb drive to replace the drive. I am
>>> asking because my case/motherboard does not have another HD slot to
>>> add the new disk
>>> in parallel with raid6. I was thinking of shutting down the machines,
>>> moving the 4tb memmebr and the new drive to another machine, making
>>> image copy (only 2tb), and putting the
>>> 2tb drive back in the original machine and rebooting. Will this work?
>>
>>
>> I think it should work, if metadata is 1.1 or 1.2 . I'm not sure if it is 1.0 .
>> You can also attach it via USB with an adapter, and do a replace (look up "want_replacement") then shutdown, swap the drives, and turn on again.
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> I thought about USB. First I do not have one, but that is a small problem to overcome. I was thinking more in terms of
> performance. USB will slow things down as it is 2.0 (old MB) and dd should be real fast (130+ MB, based on the replacement)
> But, I agree that mdadm replace is safer. Do I have to remove bitmap for replacement? I don't think so, but this is a newer operation and less info is available, so making sure.
>
> Ramesh
>
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