From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45B91C433ED for ; Tue, 18 May 2021 18:31:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2277A60D07 for ; Tue, 18 May 2021 18:31:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345860AbhERScv (ORCPT ); Tue, 18 May 2021 14:32:51 -0400 Received: from mail.thelounge.net ([91.118.73.15]:55857 "EHLO mail.thelounge.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244333AbhERSco (ORCPT ); Tue, 18 May 2021 14:32:44 -0400 Received: from srv-rhsoft.rhsoft.net (rh.vpn.thelounge.net [10.10.10.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-256)) (No client certificate requested) (Authenticated sender: h.reindl@thelounge.net) by mail.thelounge.net (THELOUNGE MTA) with ESMTPSA id 4Fl4Mc2vjkzXN3; Tue, 18 May 2021 20:31:24 +0200 (CEST) Subject: Re: My superblocks have gone missing, can't reassemble raid5 To: Phil Turmel , Roman Mamedov , Roger Heflin Cc: Christopher Thomas , Linux RAID References: <20210517112844.388d2270@natsu> <20210517181905.6f976f1a@natsu> <2e37cf64-1696-a5ca-f7db-83a1d098133d@turmel.org> From: Reindl Harald Organization: the lounge interactive design Message-ID: Date: Tue, 18 May 2021 20:31:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <2e37cf64-1696-a5ca-f7db-83a1d098133d@turmel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Am 18.05.21 um 19:47 schrieb Phil Turmel: > On 5/17/21 9:19 AM, Roman Mamedov wrote: >> On Mon, 17 May 2021 05:36:42 -0500 >> Roger Heflin wrote: >> >>> When I look at my 1.2 block, the mdraid header appears to start at >>> 4k, and >>> the gpt partition table starts at 0x0000 and ends before 4k. >>> >>> He may be able to simply delete the partition and have it work. >> >> Christopher wrote that he tried: >> >> chris@ursula:~$ sudo /sbin/mdadm --verbose --assemble /dev/md0 >> /dev/sdb /dev/sdc /dev/sdd >> mdadm: looking for devices for /dev/md0 >> mdadm: Cannot assemble mbr metadata on /dev/sdb >> mdadm: /dev/sdb has no superblock - assembly aborted >> >> I would have expected mdadm when passed entire devices (not >> partitions) to not >> even look if there are any partitions, and directly proceed to >> checking if >> there's a superblock at its supposed location. But maybe indeed, from the >> messages it looks like it bails before that, on seeing "mbr metadata", >> i.e. >> the enclosing MBR partition table of GPT. >> > > The Microsoft system partition starts on top of the location for v1.2 > metadata. > > Just another reason to *never* use bare drives the most important is that you have no guarantee that a replacement drive years later is 100% identical in size leave some margin and padding around the used space solves that problem entirely and i still need to hear a single valid reason for using unpartitioned drives in a RAID