From mboxrd@z Thu Jan 1 00:00:00 1970 From: Killian De Volder Subject: Re: Can I replace raid6 disk using dd? Date: Tue, 19 Aug 2014 09:09:34 +0200 Message-ID: <53F2F82E.7070204@megasoft.be> References: <53F2B6D8.4030208@shiftmail.org> <53F2BB43.4030408@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <53F2BB43.4030408@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Ram Ramesh , Ethan Wilson Cc: linux-raid List-Id: linux-raid.ids 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. >> -- >> 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 > 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 > > -- > 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