From owner-freebsd-fs@FreeBSD.ORG Wed Apr 27 05:42:24 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 C93F3106566B; Wed, 27 Apr 2011 05:42:24 +0000 (UTC) (envelope-from jhellenthal@gmail.com) Received: from mail-gw0-f54.google.com (mail-gw0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id 375D68FC12; Wed, 27 Apr 2011 05:42:24 +0000 (UTC) Received: by gwb15 with SMTP id 15so632861gwb.13 for ; Tue, 26 Apr 2011 22:42:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:sender:date:from:to:cc:subject:message-id :references:mime-version:content-type:content-disposition :in-reply-to:x-openpgp-key-id:x-openpgp-key-fingerprint :x-openpgp-key-url; bh=EQdtlnsz/Z0UWASKx6eLaUptXCOG7UX9hb9Si7ThmHo=; b=TWuBZs2SLHrgaWPyDT1FGofWL2d5Iusne0khQlueRffCqWC1s3UHvlAYDHDmNZB4U0 aNjhtn1FDfsgjW/ngLV0lDorGxz8kjQ27XoO2muAKLvutk/5KLbSxqw+3t7vpNcAFkSO qBIq87ogGSx4TwSMd/n/xqihfsAN4UGQu8lZM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:x-openpgp-key-id :x-openpgp-key-fingerprint:x-openpgp-key-url; b=kpesfuLXmocaKC3LywVuzQdj2qOQA5f3WdH3ejL/DkxAQBo+prdBs5DnZlyN9VghcI 7D0lEgotXxx8z9RZ1GXgdctzca13iyaVS963qwsxQKxkoglm2YPZGgZzq74Nci4gbOfU JSNV22gC1OyUIJo3cSrCNmpPsVz/YTcva4NuU= Received: by 10.151.131.15 with SMTP id i15mr1474208ybn.386.1303882943555; Tue, 26 Apr 2011 22:42:23 -0700 (PDT) Received: from DataIX.net (adsl-99-190-84-116.dsl.klmzmi.sbcglobal.net [99.190.84.116]) by mx.google.com with ESMTPS id w15sm701559ybk.1.2011.04.26.22.42.21 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 26 Apr 2011 22:42:22 -0700 (PDT) Sender: "J. Hellenthal" Received: from DataIX.net (localhost [127.0.0.1]) by DataIX.net (8.14.4/8.14.4) with ESMTP id p3R5gJhh090388 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 27 Apr 2011 01:42:19 -0400 (EDT) (envelope-from jhell@DataIX.net) Received: (from jhell@localhost) by DataIX.net (8.14.4/8.14.4/Submit) id p3R5gIZ9090387; Wed, 27 Apr 2011 01:42:18 -0400 (EDT) (envelope-from jhell@DataIX.net) Date: Wed, 27 Apr 2011 01:42:18 -0400 From: "Jason J. Hellenthal" To: Doug Barton Message-ID: <20110427054218.GA88420@DataIX.net> 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="KsGdsel6WgEHnImy" Content-Disposition: inline In-Reply-To: <4DB759A1.4050201@FreeBSD.org> X-OpenPGP-Key-Id: 0x89D8547E X-OpenPGP-Key-Fingerprint: 85EF E26B 07BB 3777 76BE B12A 9057 8789 89D8 547E X-OpenPGP-Key-URL: http://bit.ly/0x89D8547E Cc: freebsd-fs@freebsd.org, Alexander Motin , Alexander Best 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 05:42:24 -0000 --KsGdsel6WgEHnImy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 26, 2011 at 04:47:45PM -0700, Doug Barton wrote: >On 04/26/2011 16:04, Mikael Fridh wrote: >> Are labels such a perilous affair that you can't just start >> recommending them and/or default to them? > >As far as I can tell, yes. We have various different tools that do=20 >different things, all calling themselves "labels" which don't all work=20 >together well. It's also unclear how many (if any) of those solutions=20 >will survive the file system being newfs'ed. > >I made this point elsewhere, but this is an area where linux really has=20 >us beat. At install time a UUID is created for a file system if it=20 >doesn't already have one and it's referred to that way in fstab. My=20 >understanding (although I have yet to test it) is that they survive=20 >newfs because they are not located on the fs itself. When I first saw=20 >this I thought it was ugly (read, different) but having worked with it a= =20 >little bit I think it's a much superior method, and would have made the=20 >current concerns completely irrelevant.=20 >http://www.linux.com/archive/feature/146951 > Hi Doug, I do not know if this was summed up in a easy way by Jeremy's nice message below but in short a summary can be made here to clear that up. /dev/gptid/* /dev/gpt/* * These survive its raw partition being newfs'd * Are only created for disks that are partitioned and contain a GPT table as can be seen with gpart show * Operations on these or the raw partition will not remove them. /dev/ufsid/* /dev/ufs/* * Will not survive a newfs * Are created upon being newfs'd * /dev/ufs/* is the equiv of (tunefs -L) * /dev/ufsid/* is only created by newfs(8) * Operations on these or the raw slice will not remove them. /dev/label/* * Are created by glabel(8) * Will remain with the disk until its raw disk is newfs'd or data overwrites the metadata on the raw disk. * When created only the label should be newfs'd directly as a new on the disk itself would overwrite the metadata stored. * Operations on the label itself is only supported to retain the metadata. =09 The best possible thing you could use here is a GPT scheme for the disks to remain consistent across newfs's. But relying on GPT for all disks will not always work in situations where the disk also involves a operating system that does not support booting off of a GPT disk, like all of Windows XP and then Win7 for non-Itanium based architectures. Yes Win7 last checked was said to only support booting GPT schemes on Itanium systems, so this leaves a lot of systems to only rely on /dev/ufs*/ labels or generic labels. --=20 Regards, (jhell) Jason Hellenthal --KsGdsel6WgEHnImy Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (FreeBSD) Comment: http://bit.ly/0x89D8547E iQEcBAEBAgAGBQJNt6y5AAoJEJBXh4mJ2FR+oKAH/05PIBZ2f4QMu5Byb/l0MK7l VR0bjcbwUQg+bYnqDPKwIfUCwo/kfiVYOnlFkAiMA5EBKlR9K/P2XYUHa3edE/ss 2AuO/aOjBqv/TOpVN/N9XsB8zHexu5A5/rZxN1FRSTiK/oKLanhmc69UO5tJqUxm PIEzTunKF4GhG8jBj83q8GFyPLhWiegArTuKgaYs2XgWYAH+5SWVYk1OFfLNxfcz kYM/mHDOlzzASm4axiXa7I+iGFRvoy5W7hNry/aAm4wMu8GOL+gtSkA17O8THEuT R9gugndpnvrL2rinaZyr+QPf1R60EwxNO9FVkEpRkJmPQEefVb4XDE/anoWCV4M= =BqRe -----END PGP SIGNATURE----- --KsGdsel6WgEHnImy--