From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1FO6fC-0005mf-39 for mharc-grub-devel@gnu.org; Tue, 28 Mar 2006 00:22:42 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1FO6fA-0005kN-8B for grub-devel@gnu.org; Tue, 28 Mar 2006 00:22:40 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1FO6f8-0005ji-8Y for grub-devel@gnu.org; Tue, 28 Mar 2006 00:22:39 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1FO6f8-0005je-56 for grub-devel@gnu.org; Tue, 28 Mar 2006 00:22:38 -0500 Received: from [204.127.200.81] (helo=sccrmhc11.comcast.net) by monty-python.gnu.org with esmtp (Exim 4.52) id 1FO6gm-0006Mb-OT for grub-devel@gnu.org; Tue, 28 Mar 2006 00:24:20 -0500 Received: from [192.168.1.35] (c-67-163-39-124.hsd1.il.comcast.net[67.163.39.124]) by comcast.net (sccrmhc11) with ESMTP id <20060328052236011002rtd2e>; Tue, 28 Mar 2006 05:22:37 +0000 Message-ID: <4428C79F.6060106@personnelware.com> Date: Mon, 27 Mar 2006 23:20:31 -0600 From: Carl Karsten User-Agent: Thunderbird 2.0a1 (Windows/20060327) MIME-Version: 1.0 To: The development of GRUB 2 References: <44209DCE.4070208@personnelware.com> <87d5gelv81.fsf@xs4all.nl> <44289B57.1010906@personnelware.com> In-Reply-To: <44289B57.1010906@personnelware.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: software raid1 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Mar 2006 05:22:40 -0000 Carl Karsten wrote: > Marco Gerards wrote: >> Carl Karsten writes: >> >>> I have been messing around with software raid1 - mirroring 2 drives - >>> including the boot sectors. The goal is to be able to remove either >>> drive and still have a functioning system. >>> >>> I realize that this is "not supported" given that "Add support for >>> software RAID" is on the http://grub.enbug.org/TodoList but I have >>> heard it can be done with some trickery: install grub on both drives >>> and rely on the fact that /dev/hda1 and /dev/hda2 and /dev/md0 are all >>> "the same thing" as long as md0 is the only one that gets written to. >> >> RAID is more than just mirroring. You can have striping, a RAID setup >> with striping and a parity disk, etc. >> >> And besides that, even mirroring can do more advanced stuff. Like >> speeding up loading of kernels by loading from both disks and being >> more robust against broken disks. But I do not know if this can be >> realized. > > Having everything would be great - but I think just achieving the > simplest case of fault tolerance would be a very good return on investment. > > I think I have achieved it by doing (search web again...) what someone > did last year: http://www.linuxsa.org.au/mailing-list/2003-07/1270.html > > My short version: > > 1. Basic Linux install: / and everything (therefor /boot) on hda1 (no raid) > > boot a live CD and run this script: > > #mkraid.sh > > # Change the partition type of hda1 to fd (raid autodetect) > echo ,,fd,|sfdisk --force /dev/hda -N1 > > # Copy the partition table from hda to hdc: > sfdisk --no-reread -d /dev/hda | sfdisk --no-reread --force /dev/hdc > > # Set up md device > mdadm --create /dev/md0 --level=raid1 --raid-devices=2 /dev/hda1 /dev/hdc1 > > # Make hdc bootable: > grub << EOF > root (hd1,0) > setup (hd1) > EOF > > This runs. I think it even works. I was wrong. md0 is hda1 + hdc1, but even after changing boot/grub/menu.lst and fstab entries from hda1 to md0, hda1 still gets mounted on /, but RO and then nothing works. when I boot to a live CD, it looks like md0 should go, but I am missing somehting. btw - "I also need a scipt line to change hda1 to md0." is for manu.lst and fstab. suggestions welcome. I am starting on step 1 once again. Carl