Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758025Ab0BMT6P (ORCPT ); Sat, 13 Feb 2010 14:58:15 -0500 Received: from terminus.zytor.com ([198.137.202.10]:52933 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757904Ab0BMT6N (ORCPT ); Sat, 13 Feb 2010 14:58:13 -0500 Message-ID: <4B77044B.1020609@zytor.com> Date: Sat, 13 Feb 2010 11:58:03 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc11 Thunderbird/3.0.1 MIME-Version: 1.0 To: Michael Evans CC: Justin Piszcz , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Linux mdadm superblock question. References: <4877c76c1002111752h23e14f7aibe58a89181e6f493@mail.gmail.com> In-Reply-To: <4877c76c1002111752h23e14f7aibe58a89181e6f493@mail.gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1802 Lines: 45 On 02/11/2010 05:52 PM, Michael Evans wrote: > On Thu, Feb 11, 2010 at 3:00 PM, Justin Piszcz wrote: >> Hi, >> >> I may be converting a host to ext4 and was curious, is 0.90 still the only >> superblock version for mdadm/raid-1 that you can boot from without having to >> create an initrd/etc? >> >> Are there any benefits to using a superblock > 0.90 for a raid-1 boot volume >> < 2TB? >> >> Justin. >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > You need the superblock at the end of the partition: If you read the > manual that is clearly either version 0.90 OR 1.0 (NOT 1.1 and also > NOT 1.2; those use the same superblock layout but different > locations). 0.9 has the *serious* problem that it is hard to distinguish a whole-volume However, apparently mdadm recently switched to a 1.1 default. I strongly urge Neil to change that to either 1.0 and 1.2, as I have started to get complaints from users that they have made RAID volumes with newer mdadm which apparently default to 1.1, and then want to boot from them (without playing MBR games like Grub does.) I have to tell them that they have to regenerate their disks -- the superblock occupies the boot sector and there is nothing I can do about it. It's the same pathology XFS has. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/