From mboxrd@z Thu Jan 1 00:00:00 1970 From: Digimer Subject: Re: Broken array, trying to assemble enough to copy data off Date: Thu, 10 Oct 2013 12:54:44 -0400 Message-ID: <5256DBD4.4030906@alteeve.ca> References: <5255E5E4.8010900@alteeve.ca> <5255E98C.3020009@alteeve.ca> <5256A14B.7030008@turmel.org> <5256D3C4.5010109@alteeve.ca> <5256D773.2010808@turmel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5256D773.2010808@turmel.org> Sender: linux-raid-owner@vger.kernel.org To: Phil Turmel Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 10/10/13 12:36, Phil Turmel wrote: > On 10/10/2013 12:20 PM, Digimer wrote: >>> Phil >> >> Ya, I have no plan at all to use these drives or the server they came >> from anymore. In fact, they've already been replaced. :) > > That's good. > >> I tried the --assemble --force (and --assemble --force --run) without >> success. It fails saying that sde2 thinks sdb2 has failed, leaving two >> dead members. If I try to start with just sd[bcd], it says that it has >> two drives and one spare, so still refuses to start. > > Ok. > >> Any other options/ideas? I'm not in any rush, so I am happy to test things. > > Well, you have rock-solid knowledge of the device order and array > parameters. So a --create operation is the next step. Given that sdd2 > is marked as spare, and therefore of unknown value, I'd leave it out. > > mdadm --stop /dev/md1 > mdadm --create --level=5 -n 4 --chunk=512 /dev/md1 \ > /dev/sd{c,e,b}2 missing > > (--assume-clean isn't needed when creating a degraded raid5) > > The brace syntax is needed, not brackets, as the order matters. > > After creation, use mdadm -E to verify the Data Offset is 2048. If not, > get a new version of mdadm that lets you specify it. > > Only after that should you use "fsck -n" to verify your filesystem and > mount it. > > HTH, > > Phil What if I don't have rock-solid knowledge? Is there a way to connect the four drives and query them to determine which is which? I was using the new system (minus the new drives) plus a spare new 500GB drive with the fresh centos install to do the testing yesterday. I am pretty sure I can redo the cabling to match, but I always prefer safe over sorry. :) Thanks very much for your help so far! digimer -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?