Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965008AbWBGKnO (ORCPT ); Tue, 7 Feb 2006 05:43:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965005AbWBGKnO (ORCPT ); Tue, 7 Feb 2006 05:43:14 -0500 Received: from percy.comedia.it ([212.97.59.71]:28806 "EHLO percy.comedia.it") by vger.kernel.org with ESMTP id S964994AbWBGKnN (ORCPT ); Tue, 7 Feb 2006 05:43:13 -0500 Date: Tue, 7 Feb 2006 11:43:11 +0100 From: Luca Berra To: "H. Peter Anvin" Cc: Neil Brown , linux-raid@vger.kernel.org, klibc list , Linux Kernel Mailing List Subject: Re: [klibc] Re: Exporting which partitions to md-configure Message-ID: <20060207104311.GD22221@percy.comedia.it> Mail-Followup-To: "H. Peter Anvin" , Neil Brown , linux-raid@vger.kernel.org, klibc list , Linux Kernel Mailing List References: <43DEB4B8.5040607@zytor.com> <17374.47368.715991.422607@cse.unsw.edu.au> <43DEC095.2090507@zytor.com> <17374.50399.1898.458649@cse.unsw.edu.au> <43DEC5DC.1030709@zytor.com> <17382.43646.567406.987585@cse.unsw.edu.au> <43E80A5A.5040002@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <43E80A5A.5040002@zytor.com> User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2459 Lines: 58 On Mon, Feb 06, 2006 at 06:47:54PM -0800, H. Peter Anvin wrote: >Neil Brown wrote: >Requiring that mdadm.conf describes the actual state of all volumes >would be an enormous step in the wrong direction. Right now, the Linux >md system can handle some very oddball hardware changes (such as on >hera.kernel.org, when the disks not just completely changed names due to >a controller change, but changed from hd* to sd*!) DEVICE partitions ARRAY /dev/md0 UUID=xxyy:zzyy:aabb:ccdd would catch that >Dynamicity is a good thing, although it needs to be harnessed. > > > kernel parameter md_root_uuid=xxyy:zzyy:aabb:ccdd... > > This could be interpreted by an initramfs script to run mdadm > > to find and assemble the array with that uuid. The uuid of > > each array is reasonably unique. I could change mdassemble to allow accepting an uuid on the command line and assemble a /dev/md0 with the specified uuid (at the moment it only accepts a configuration file, which i tought was enough for initrd/initramfs. >This, in fact is *EXACTLY* what we're talking about; it does require >autoassemble. Why do we care about the partition types at all? The >reason is that since the md superblock is at the end, it doesn't get >automatically wiped if the partition is used as a raw filesystem, and so >it's important that there is a qualifier for it. I don't like using partition type as a qualifier, there is people who do not wish to partition their drives, there are systems not supporting msdos like partitions, heck even m$ is migrating away from those. In any case if that has to be done it should be done into mdadm, not in a different scrip that is going to call mdadm (behaviour should be consistent between mdadm invoked by initramfs and mdadm invoked on a running system). If the user wants to reutilize a device that was previously a member of an md array he/she should use mdadm --zero-superblock to remove the superblock. I see no point in having a system that tries to compensate for users not following correct procedures. sorry. L. -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/