Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756752AbdCWVLa (ORCPT ); Thu, 23 Mar 2017 17:11:30 -0400 Received: from box.mueller.org ([45.79.158.33]:43860 "EHLO mail.mueller.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755637AbdCWVL3 (ORCPT ); Thu, 23 Mar 2017 17:11:29 -0400 Subject: Re: RAID array is gone, please help To: Lennart Sorensen References: <20170323173721.GA14188@csclub.uwaterloo.ca> <87d1da5c-a39b-fd41-62a7-640b0eea5501@mueller.org> <20170323192726.GM14186@csclub.uwaterloo.ca> <9dcb25dc-52f3-f831-6115-6a7feb07de1c@mueller.org> <20170323195903.GO14186@csclub.uwaterloo.ca> <28c5f9ba-c312-0439-9d8a-78e06c3f00f0@mueller.org> <20170323210908.GQ14186@csclub.uwaterloo.ca> Cc: linux-kernel@vger.kernel.org From: Stephen Mueller Message-ID: Date: Thu, 23 Mar 2017 22:11:25 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170323210908.GQ14186@csclub.uwaterloo.ca> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 36 First I'm getting the data off the RAID... then I'm going to delete the whole thing again... create a new RAID using partitions... follow every step carefully... then once the new RAID array is there, I'll throw a bit of data on it, and then reboot and see if it's still there... if so, I'll repopulate all the data. Thanks. On 3/23/2017 22:09, Lennart Sorensen wrote: > On Thu, Mar 23, 2017 at 10:02:23PM +0100, Stephen Mueller wrote: >> Looks like it worked! Thanks! > > Well at least you could backup the data, just in case. > >> I used: >> >> sudo mdadm --create /dev/md0 --assume-clean --verbose --level-10 >> --raid-devices=4 /dev/sdc /dev/sdd /dev/sde /dev/sdf > > I wonder about the assume-clean, but I would think any data you wrote > will have been duplicated at the time you wrote it, and only unused > space might not have been synced yet. > > Maybe running a forced resync would be worthwhile. > >> And I got my instructions for creating the array here, and they >> also don't use partitions... >> >> https://www.digitalocean.com/community/tutorials/how-to-create-raid-arrays-with-mdadm-on-ubuntu-16-04 > > Well it works, as long as you don't leave anything around to confuse it, > in this case a GPT partition table that somehow came back to bite you. > > I wonder if mdadm could perhaps warn about the existing partition table > when being asked to create a new device. > > Does it survive reboots now? >