From owner-freebsd-questions@FreeBSD.ORG Thu Aug 23 09:51:58 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2238A16A419 for ; Thu, 23 Aug 2007 09:51:58 +0000 (UTC) (envelope-from xfb52@dial.pipex.com) Received: from galaxy.systems.pipex.net (galaxy.systems.pipex.net [62.241.162.31]) by mx1.freebsd.org (Postfix) with ESMTP id DE1E113C458 for ; Thu, 23 Aug 2007 09:51:57 +0000 (UTC) (envelope-from xfb52@dial.pipex.com) Received: from [192.168.23.2] (62-31-10-181.cable.ubr05.edin.blueyonder.co.uk [62.31.10.181]) by galaxy.systems.pipex.net (Postfix) with ESMTP id 39F43E00049A; Thu, 23 Aug 2007 10:51:55 +0100 (BST) Message-ID: <46CD58BB.9080001@dial.pipex.com> Date: Thu, 23 Aug 2007 10:51:55 +0100 From: Alex Zbyslaw User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-GB; rv:1.7.13) Gecko/20061205 X-Accept-Language: en MIME-Version: 1.0 To: Jerry McAllister , Christopher Key , freebsd-questions@freebsd.org References: <46CC1DB7.7040506@cam.ac.uk> <20070822152326.GF56142@gizmo.acns.msu.edu> In-Reply-To: <20070822152326.GF56142@gizmo.acns.msu.edu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: FreeBSD MBRs X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Aug 2007 09:51:58 -0000 Jerry McAllister wrote: >You only need an MBR on disks that will be booted. I don't know as >it will actually hurt anything to write an MBR on non-boot, data only >disks, but it can garbage up you menu with non-functional choices. > > What you need is an MBR on every disk which is *passed through* or actually booted from. So if you have disks 1, 2 &3, if you want to boot from disk3 you need an MBR on disks 1 & 2 as well, even if you never boot from them. If you boot from disk 1, then 2 &3 do not *need* an MBR. >Those other disk with an MBR show up as an F5 and maybe F6, etc ( > F5 is the *next* disk. There is no F6, F7 etc. If you boot from disk 3, for example, you'd go through three "menus" e.g. Disk1: F5 -> disk2 Disk2: F5 -> disk3 Disk3: F1 -> boots FreeBSD If those were your only 3 disks, then F5 on disk3 takes you back to disk1. You can probably change the boot order of those disks in your BIOS to make disk3 be disk1, avoiding the intermediate menus. That's not always possible for other reasons. For example, in the setup above, if disk 1 has Windows on it and that really does work best as disk1. If disk 2 is on the same controller as disk 1 your BIOS might not allow that to be changed independently. I know of no reason why you wouldn't want the MBR on all your disks, even if you don't technically need it. Sorry, no idea if this helps with the original question, which I too had trouble following. --Alex