From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ram Ramesh Subject: Re: Can I replace raid6 disk using dd? Date: Mon, 18 Aug 2014 21:49:39 -0500 Message-ID: <53F2BB43.4030408@gmail.com> References: <53F2B6D8.4030208@shiftmail.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <53F2B6D8.4030208@shiftmail.org> Sender: linux-raid-owner@vger.kernel.org To: Ethan Wilson Cc: linux-raid List-Id: linux-raid.ids 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