Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758031Ab0BMUt0 (ORCPT ); Sat, 13 Feb 2010 15:49:26 -0500 Received: from mail.lang.hm ([64.81.33.126]:37370 "EHLO bifrost.lang.hm" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751009Ab0BMUtY (ORCPT ); Sat, 13 Feb 2010 15:49:24 -0500 Date: Sat, 13 Feb 2010 12:49:13 -0800 (PST) From: david@lang.hm X-X-Sender: dlang@asgard.lang.hm To: Justin Piszcz cc: "H. Peter Anvin" , Michael Evans , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Linux mdadm superblock question. In-Reply-To: Message-ID: References: <4877c76c1002111752h23e14f7aibe58a89181e6f493@mail.gmail.com> <4B77044B.1020609@zytor.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2135 Lines: 57 On Sat, 13 Feb 2010, Justin Piszcz wrote: > On Sat, 13 Feb 2010, H. Peter Anvin wrote: > >> 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 >> > > My original question was does the newer superblock do anything special or > offer new features *BESIDES* the quicker resync? the older superblocks have limits on the number of devices that can be part of the raid set. David Lang -- 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/