From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 17 Jan 2001 19:43:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 17 Jan 2001 19:42:49 -0500 Received: from [24.65.192.120] ([24.65.192.120]:14832 "EHLO webber.adilger.net") by vger.kernel.org with ESMTP id ; Wed, 17 Jan 2001 19:41:31 -0500 From: Andreas Dilger Message-Id: <200101180039.f0I0du929822@webber.adilger.net> Subject: Re: Linux not adhering to BIOS Drive boot order? In-Reply-To: "from Tim Fletcher at Jan 18, 2001 00:14:42 am" To: Tim Fletcher Date: Wed, 17 Jan 2001 17:39:56 -0700 (MST) CC: Andreas Dilger , Werner Almesberger , Venkatesh Ramamurthy , linux-kernel@vger.kernel.org X-Mailer: ELM [version 2.4ME+ PL73 (25)] MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Tim Fletcher writes: > You can already do this, just specify /dev/md0 as the device to install > onto, and lilo does the rest > > > This would potentially allow you to boot from the second drive if the > > first one fails, assuming the kernel does UUID or LABEL resolution for > > the root device. The kernel would boot from the first BIOS drive, and > > would search for a UUID or LABEL as the root device. > > I have a mirrored boot drive in a pair of firewalls / routers and to test > before I put them into service I pulled hda and the machine booted fine > from hdc and baring winging about the missing disk (all the drives are > mirrored) carried on as normal. A fresh disk was put and rebuilt no > problems and was then booted off with the other disk missing. Ahh. What I was missing was that by specifying /dev/md0 as the root device, not only do you get an identical map for the kernels, but the root device remains /dev/md0 no matter which drive fails and LILO/kernel don't need to do anything special to find it. This assumes the BIOS can boot from /dev/hdc to start with (i.e. /dev/hda is totally gone). How does MD/RAID0 know which array should be /dev/md0? What if you had a second array on /dev/hdb and /dev/hdd, would that become /dev/md0 (assuming it had a kernel/boot sector)? Cheers, Andreas -- Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto, \ would they cancel out, leaving him still hungry?" http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/