From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1PjwrQ-0000qw-AW for mharc-grub-devel@gnu.org; Mon, 31 Jan 2011 11:44:16 -0500 Received: from [140.186.70.92] (port=59260 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PjwrK-0000nI-19 for grub-devel@gnu.org; Mon, 31 Jan 2011 11:44:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PjwrF-0000ec-7Y for grub-devel@gnu.org; Mon, 31 Jan 2011 11:44:09 -0500 Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122]:40692) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PjwrF-0000bx-0p for grub-devel@gnu.org; Mon, 31 Jan 2011 11:44:05 -0500 Authentication-Results: cdptpa-omtalb.mail.rr.com smtp.user=psusi@cfl.rr.com; auth=pass (PLAIN) X-Authority-Analysis: v=1.1 cv=pepdxKapwHuwCZNFD5uob2wvham6E+RljB0uXw08FdQ= c=1 sm=0 a=8nJEP1OIZ-IA:10 a=pg4Dpxby4z7sZisWVyJ9NA==:17 a=NaWYLVkytZnGpaOmhIcA:9 a=lIKAOaCm7YI-Wlxa64gA:7 a=sQA1Yg0wSGdOs16X3ynIahZpcvEA:4 a=wPNLvfGTeEIA:10 a=pg4Dpxby4z7sZisWVyJ9NA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 72.242.190.170 Received: from [72.242.190.170] ([72.242.190.170:4651] helo=[10.1.1.235]) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTPA id 98/F0-19545-0D6E64D4; Mon, 31 Jan 2011 16:44:01 +0000 Message-ID: <4D46E6D7.2000205@cfl.rr.com> Date: Mon, 31 Jan 2011 11:44:07 -0500 From: Phillip Susi User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 MIME-Version: 1.0 To: The development of GNU GRUB 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> In-Reply-To: <4D01328D.9050503@cfl.rr.com> X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 75.180.132.122 Cc: Neil Brown , linux-raid@vger.kernel.org, John Sheu 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 16:44:13 -0000 I know you went on vacation over the new year, but it has been about two months now so I figured I would try to revive this conversation. Having collected my thoughts, this is what I propose: I believe that right now, grub recognizes an md device that is built on partitions, and installs to the underlying disks. When the device is built on the whole disks, it needs to divide into two categories: 1) Native md metadata. Grub should ask mdadm for a suitable location to embed the core image on each component disk. This can be satisfied with a 32kb area at the end ( or maybe the beginning ) of the disk that is not used by the array ( or the metadata ). This will work for all native formats except for 1.1, for the obvious reason that it is using the boot block. 2) Other metadata formats. Either assume or explicitly be told by mdadm that these formats are fakeraid and thus understood by the bios int 13. Grub installs to the array as a whole, just like it does today when they are handled by dmraid. If it is known that it is not bios supported, then error out. In the future this could be supported by creating additional grub modules that understand those metadata formats. One question that needs answered for method 1 is what should the partition table look like? Should grub, or maybe mdadm, create a protective mbr when using the whole disk, similar to the one used with GPT?