From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1Pk38e-0007s7-C4 for mharc-grub-devel@gnu.org; Mon, 31 Jan 2011 18:26:28 -0500 Received: from [140.186.70.92] (port=44855 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pk1zT-0001IA-8T for grub-devel@gnu.org; Mon, 31 Jan 2011 17:12:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pk1zR-0000pD-Dk for grub-devel@gnu.org; Mon, 31 Jan 2011 17:12:55 -0500 Received: from caffeine.csclub.uwaterloo.ca ([129.97.134.17]:50250) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pk1zR-0000oY-AW for grub-devel@gnu.org; Mon, 31 Jan 2011 17:12:53 -0500 Received: by caffeine.csclub.uwaterloo.ca (Postfix, from userid 20367) id 92DD410F1; Mon, 31 Jan 2011 17:12:52 -0500 (EST) Date: Mon, 31 Jan 2011 17:12:52 -0500 To: The development of GNU GRUB Message-ID: <20110131221252.GT343@caffeine.csclub.uwaterloo.ca> References: <4CF55680.5010703@cfl.rr.com> <20101201092508.7023f974@notabene.brown> <4CF81A16.2010606@cfl.rr.com> <20101203123615.6edce071@notabene.brown> <4CF860EB.7010005@cfl.rr.com> <20101209094354.4c6aaa93@notabene.brown> <4D01328D.9050503@cfl.rr.com> <4D46E6D7.2000205@cfl.rr.com> <20110131170349.GR343@caffeine.csclub.uwaterloo.ca> <4D470BCF.20508@cfl.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D470BCF.20508@cfl.rr.com> User-Agent: Mutt/1.5.18 (2008-05-17) From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 129.97.134.17 Cc: Neil Brown , linux-raid@vger.kernel.org, John Sheu , Lennart Sorensen Subject: Re: Software RAID and Fakeraid X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 31 Jan 2011 23:26:26 -0000 On Mon, Jan 31, 2011 at 02:21:51PM -0500, Phillip Susi wrote: > That is why I asked what the partition table should look like. When > grub is installed there will be one ( and boot code ), the question is > whether it should be empty, or have a protective partition that claims > the entire disk, like EFI does. > > Normally with format 0.9, the raid array starts on sector 0, so the same > MBR appears both at the start of the first physical disk, and at the > start of the array. This is not possible with 1.1 or 1.2, so where do > they start the array? I must be at some point further away from sector > 0, leaving room for a protective MBR on the component disks that would > be entirely separate from any MBR inside the array. This leaves room > for grub to be installed on each component disk, rather than only the > first. It also means that it is incompatible with formats 0.9, 1.1, and > possibly 1.0, depending on whether it includes the first sector in the > array like 0.9 does. Well one of them stores the raid info at the end of the device, so that one offers no help for the bootloader at all. I think the other stores it at 4KB in to the device if my memory serves me right. Not sure if the first 4KB are left empty for other uses or not. It seems to me the simplest thing to do is to simply state in documentation that grub can not be installed on md raid if there is no partition table in use. This doesn't mean people can't do it for purely data oriented drives, but for the drives with the boot laoder there are limitations. -- Len Sorensen