Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756695AbdCWVCi (ORCPT ); Thu, 23 Mar 2017 17:02:38 -0400 Received: from box.mueller.org ([45.79.158.33]:43808 "EHLO mail.mueller.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752775AbdCWVCh (ORCPT ); Thu, 23 Mar 2017 17:02:37 -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> Cc: linux-kernel@vger.kernel.org From: Stephen Mueller Message-ID: <28c5f9ba-c312-0439-9d8a-78e06c3f00f0@mueller.org> Date: Thu, 23 Mar 2017 22:02:23 +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: 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: 1983 Lines: 60 Looks like it worked! Thanks! I used: sudo mdadm --create /dev/md0 --assume-clean --verbose --level-10 --raid-devices=4 /dev/sdc /dev/sdd /dev/sde /dev/sdf 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 On 3/23/2017 21:09, Stephen Mueller wrote: > OK, I used gdisk to remove the GPT and MBR from each disk. > mdadm --assemble still doesn't work... says it can't find the > superblock. The mdadm --examine commands also say that no > superblock is detected. > > I guess I'll go ahead with --create... > > > On 3/23/2017 20:59, Lennart Sorensen wrote: >> On Thu, Mar 23, 2017 at 08:38:08PM +0100, Stephen Mueller wrote: >>> Apologies, I should have started this on linux-raid... >>> >>> >>> stephen@fred> sudo gdisk -l /dev/sdc >>> GPT fdisk (gdisk) version 1.0.1 >>> >>> Partition table scan: >>> MBR: protective >>> BSD: not present >>> APM: not present >>> GPT: present >>> >>> Found valid GPT with protective MBR; using GPT. >>> Disk /dev/sdc: 7814037168 sectors, 3.6 TiB >>> Logical sector size: 512 bytes >>> Disk identifier (GUID): 60F1D54C-9D17-4688-BD6E-447F5E7408EB >>> Partition table holds up to 128 entries >>> First usable sector is 34, last usable sector is 7814037134 >>> Partitions will be aligned on 2048-sector boundaries >>> Total free space is 7814037101 sectors (3.6 TiB) >>> >>> Number Start (sector) End (sector) Size Code Name >>> stephen@fred> >>> >>> The other disks are all similar. >>> >>> How do I remove the MBR/GPT tables? So you would do that, and then the >>> mdadm --create? >> >> Well at least that seems to confirm that something restored the GPT from >> the second copy at the end of the disk, wiping out the md superblock >> at 4k. >> >> If you run gdisk /dev/sdc, it has a 'zap' option using the z key to >> delete all traces of GPT. That ought to do what you want. >>