From owner-freebsd-fs@FreeBSD.ORG Wed Apr 27 21:25:26 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4CE871065675 for ; Wed, 27 Apr 2011 21:25:26 +0000 (UTC) (envelope-from peterjeremy@acm.org) Received: from mail12.syd.optusnet.com.au (mail12.syd.optusnet.com.au [211.29.132.193]) by mx1.freebsd.org (Postfix) with ESMTP id D0AD88FC19 for ; Wed, 27 Apr 2011 21:25:25 +0000 (UTC) Received: from server.vk2pj.dyndns.org (c220-239-116-103.belrs4.nsw.optusnet.com.au [220.239.116.103]) by mail12.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id p3RLPNv4031127 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 28 Apr 2011 07:25:23 +1000 X-Bogosity: Ham, spamicity=0.000000 Received: from server.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by server.vk2pj.dyndns.org (8.14.4/8.14.4) with ESMTP id p3RLPMWs099526; Thu, 28 Apr 2011 07:25:22 +1000 (EST) (envelope-from peter@server.vk2pj.dyndns.org) Received: (from peter@localhost) by server.vk2pj.dyndns.org (8.14.4/8.14.4/Submit) id p3RLPMYE099525; Thu, 28 Apr 2011 07:25:22 +1000 (EST) (envelope-from peter) Date: Thu, 28 Apr 2011 07:25:21 +1000 From: Peter Jeremy To: Freddie Cash Message-ID: <20110427212521.GA99261@server.vk2pj.dyndns.org> References: <4DB70949.6090104@FreeBSD.org> <20110426182017.GA92471@freebsd.org> <4DB70F13.6060002@FreeBSD.org> <4DB759A1.4050201@FreeBSD.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="cNdxnHkX5QqsyA0e" Content-Disposition: inline In-Reply-To: X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-fs@freebsd.org Subject: Re: Why not just name the cam-ata devices the same as the old names? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Apr 2011 21:25:26 -0000 --cNdxnHkX5QqsyA0e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2011-Apr-26 22:46:20 -0700, Freddie Cash wrote: >This is where labelling *disks* is the better route. Filesystems come >and go, but the disks don't change very often. This is one the nicest >things about using FreeBSD systems (all the GEOM stacking and >labelling). But disks _do_ get changed for various reasons (eg failure). If we move to a an identification approach that is based on the physical disk, rather than some variant on the path to a disk, we need to ensure that the disk replacement procedure is well documented. One associated issue is determining what disk you are booting from - my main system has 6 disks spread across 3 controllers. Whilst the BIOS reports size and model, it doesn't report serial number (and the mapping of SATA port to legacy PATA channel/master-slave is non-obvious and as tripped me up in the past). By the time I get to loader(8), I'm just presented with 'C' through 'H' (mapped to disk0 thru disk5). There is no way to map this to either physical disk (though this is probably the fault of my BIOS) or to FreeBSD device names. loader needs to grow enough smarts to be able to report a disk serial number (where possible) and there nees to be a tool that can map between loader and FreeBSD disk names (though it's not clear whether this belongs in loader(8), the kernel, userland or some combination). As for the ad->ada renaming: I went through this some time ago (by manually switching my kernel from ata to ahci), resulting in ad{4,6,8} becoming ada{0,1,2}. Whilst I was aware of the issue, I still managed to confuse myself and I think it took me at least one reboot to get the names straight. (Thought ZFS took the renaming of the devices underlying my data pool in its stride). --=20 Peter Jeremy --cNdxnHkX5QqsyA0e Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (FreeBSD) iEYEARECAAYFAk24icEACgkQ/opHv/APuIcvqgCcCe7p4SWQf7CVdec8PodQPFSb fbMAoLMKBFtIt//aFxc2XlRuKCLEPtcx =kao1 -----END PGP SIGNATURE----- --cNdxnHkX5QqsyA0e--