From owner-freebsd-questions@FreeBSD.ORG Sun Mar 28 12:36:29 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DEAD416A4CE for ; Sun, 28 Mar 2004 12:36:29 -0800 (PST) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9915443D2D for ; Sun, 28 Mar 2004 12:36:29 -0800 (PST) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.12.10/8.12.10) id i2SKaSva079941; Sun, 28 Mar 2004 14:36:28 -0600 (CST) (envelope-from dan) Date: Sun, 28 Mar 2004 14:36:28 -0600 From: Dan Nelson To: Dan Langille Message-ID: <20040328203628.GL3446@dan.emsphone.com> References: <4066EB0D.5638.7129DAAE@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4066EB0D.5638.7129DAAE@localhost> X-OS: FreeBSD 5.2-CURRENT X-message-flag: Outlook Error User-Agent: Mutt/1.5.6i cc: freebsd-questions@freebsd.org Subject: Re: RAID - can a mirrored disk be used on a non-RAID controller? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 28 Mar 2004 20:36:30 -0000 In the last episode (Mar 28), Dan Langille said: > I had a hard disk failure this weekend. I had been considering RAID > mirroring but this has brought the issue forward. > > My plan is to create a box with two drives and use a RAID card to > mirror them. Should the RAID card die, can I move a drive to another > box with a standard IDE controller and run the system from there? In > short, I'm asking, does the RAID controller create a drive image > which cannot be used by an IDE controller? Depends on where the metadata is stored. If the controller uses the last xx sectors of the disk, then you're okay. If it uses the first, then your MBR and partition table won't be in the right place if you look at it outside of the RAID card. My guess is that it uses the first xx sectors, since that makes it easier to blank disks when you move then from machine to machine, and also prevents people from accidentally doing what you're trying to do if their array is RAID-1, RAID-5, or concatenated RAID-0 (all of which will partially work but fail spectacularly at some point if you try and access disk 1 outside of the RAID array) -- Dan Nelson dnelson@allantgroup.com