From owner-freebsd-arch@FreeBSD.ORG Tue Jun 27 11:24:09 2006 Return-Path: X-Original-To: freebsd-arch@freebsd.org Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2941116A409 for ; Tue, 27 Jun 2006 11:24:09 +0000 (UTC) (envelope-from pjd@garage.freebsd.pl) Received: from mail.garage.freebsd.pl (arm132.internetdsl.tpnet.pl [83.17.198.132]) by mx1.FreeBSD.org (Postfix) with ESMTP id AE1D243D6A for ; Tue, 27 Jun 2006 11:24:05 +0000 (GMT) (envelope-from pjd@garage.freebsd.pl) Received: by mail.garage.freebsd.pl (Postfix, from userid 65534) id C6FCF51391; Tue, 27 Jun 2006 13:24:03 +0200 (CEST) Received: from localhost (pjd.wheel.pl [10.0.1.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.garage.freebsd.pl (Postfix) with ESMTP id 6A6AD5131F; Tue, 27 Jun 2006 13:23:54 +0200 (CEST) Date: Tue, 27 Jun 2006 13:21:05 +0200 From: Pawel Jakub Dawidek To: Peter Jeremy Message-ID: <20060627112105.GC21661@garage.freebsd.pl> References: <20060626171035.GE12511@garage.freebsd.pl> <56651.1151347579@critter.freebsd.dk> <20060627080312.GB714@turion.vk2pj.dyndns.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="6zdv2QT/q3FMhpsV" Content-Disposition: inline In-Reply-To: <20060627080312.GB714@turion.vk2pj.dyndns.org> X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 7.0-CURRENT i386 User-Agent: mutt-ng/devel-r804 (FreeBSD) X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on mail.garage.freebsd.pl X-Spam-Level: X-Spam-Status: No, score=-5.9 required=3.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham version=3.0.4 Cc: Poul-Henning Kamp , freebsd-arch@freebsd.org Subject: Re: Accessing disks via their serial numbers. X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Jun 2006 11:24:09 -0000 --6zdv2QT/q3FMhpsV Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 27, 2006 at 06:03:12PM +1000, Peter Jeremy wrote: > On Mon, 2006-Jun-26 18:46:19 +0000, Poul-Henning Kamp wrote: > >>> 4. It prevents cold-state swapout of disk drives. > >> > >>Why? > > > >Because /etc/fstab contains the serial number of the disk you just > >junked and the new one has a different serial number. >=20 > I've used a couple of OSs that derived their logical disk name (ie > /dev/disk/dsk5) from the WWID by keeping a magic database to map > the WWID to the name. None of them have good solutions to telling > the OS that WWID-x has died and I want WWID-y to now map to the same > logical device as WWID-x used to. >=20 > Actually having the WWID (or similar) as the logical name would make > handling a disk swap really nasty. >=20 > Stating that the sysadmin knows about the change doesn't address the > issue: The sysadmin changed the device because the old one failed. > There may or may not have been advance notice of the replacement. I'm not saying it solves all problems, but it is very useful in certain situations, where what you mentioned is not the case. For software RAID you still has to somehow say that this driver replaced that one. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --6zdv2QT/q3FMhpsV Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD4DBQFEoRShForvXbEpPzQRAqzmAJjmsV9aZHIvTAiPIWJ/PfSn/JCUAKD0Oz9Y MHVqWYZ3kaDBoMIa4bVOyg== =AwGy -----END PGP SIGNATURE----- --6zdv2QT/q3FMhpsV--