From owner-freebsd-stable@FreeBSD.ORG Thu Sep 16 09:29:36 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C426E106566C for ; Thu, 16 Sep 2010 09:29:36 +0000 (UTC) (envelope-from stb@lassitu.de) Received: from gilb.zs64.net (gilb.zs64.net [IPv6:2001:470:1f0b:105e::1ea]) by mx1.freebsd.org (Postfix) with ESMTP id 8C20E8FC16 for ; Thu, 16 Sep 2010 09:29:36 +0000 (UTC) Received: by gilb.zs64.net (Postfix, from stb@lassitu.de) id D878C9F402; Thu, 16 Sep 2010 09:29:34 +0000 (UTC) Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii From: Stefan Bethke In-Reply-To: Date: Thu, 16 Sep 2010 11:29:33 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Michael Sperber X-Mailer: Apple Mail (2.1081) Cc: freebsd-stable@freebsd.org Subject: Re: How to predict drive number change for 7.3->8.1 upgrade? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Sep 2010 09:29:36 -0000 Am 16.09.2010 um 11:05 schrieb Michael Sperber: > I just upgraded my desktop system from 7.3 to 8.1, and the main hard > drive, which was /dev/ad6 before is now /dev/ad10. Consequently, the > initial boot failed when trying to mount the root file system from = ad6. >=20 > The desktop system is now fixed, but I also have a rented server with > only a serial console, and I worry that the upgrade is going to leave = me > with a dead machine. Is there any way to predict how the drive number > changes? (Why does it change at all?) If so, what's the proper way = to > tell the system the initial root device *before* rebooting? If you have a serial console, you can always enter the root device at = the prompt, so you can recover there. If you can figure out the new device name, you can simply change the = fstab entry for /; that's where loader picks up the root device that it = hands to the kernel. Long-term, the best option is to label your filesystems or partitions, = and use the label entries in fstab instead of the device names. I don't = remember what 7.3 offers in terms of labels, but glabel should be = available. Check tunefs if it offers the -L volname option, that's even = better. Stefan --=20 Stefan Bethke Fon +49 151 14070811