From owner-freebsd-geom@FreeBSD.ORG Wed May 25 15:24:49 2011 Return-Path: Delivered-To: freebsd-geom@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4CA311065675; Wed, 25 May 2011 15:24:49 +0000 (UTC) (envelope-from xcllnt@mac.com) Received: from asmtpout024.mac.com (asmtpout024.mac.com [17.148.16.99]) by mx1.freebsd.org (Postfix) with ESMTP id 2EC348FC12; Wed, 25 May 2011 15:24:48 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII Received: from sa-nc-common-178.static.jnpr.net (natint3.juniper.net [66.129.224.36]) by asmtp024.mac.com (Oracle Communications Messaging Exchange Server 7u4-18.01 64bit (built Jul 15 2010)) with ESMTPSA id <0LLR000ATC557C90@asmtp024.mac.com>; Wed, 25 May 2011 08:24:42 -0700 (PDT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.4.6813,1.0.148,0.0.0000 definitions=2011-05-25_07:2011-05-25, 2011-05-25, 1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=2 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=6.0.2-1012030000 definitions=main-1105250081 From: Marcel Moolenaar In-reply-to: <4DDD1C56.70706@FreeBSD.org> Date: Wed, 25 May 2011 08:24:40 -0700 Message-id: References: <4DDA2F0B.2040203@yandex.ru> <9ED563AB-7B35-40F4-A33E-015317858401@bsdimp.com> <4DDB5375.6050004@FreeBSD.org> <2FCA1E3C-E11C-46C9-A41B-E5DF4D8BA1FC@bsdimp.com> <9B250685-62F2-4AF7-BDCC-D176FA3C6FCD@mac.com> <4DDD1C56.70706@FreeBSD.org> To: Andriy Gapon X-Mailer: Apple Mail (2.1084) Cc: "Andrey V. Elsukov" , Warner Losh , freebsd-geom@FreeBSD.org Subject: Re: [RFC] Remove requirement of alignment to track from MBR scheme X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 May 2011 15:24:49 -0000 On May 25, 2011, at 8:12 AM, Andriy Gapon wrote: > on 24/05/2011 21:12 Marcel Moolenaar said the following: >> With respect to the creation: >> >> Since out synthesized geometry is not necessarily the same >> as other OSes, we could opt to synthesize a geometry that >> has a track size (= sectors/track) that is a multiple of 8 >> (to play nice with 4K sectors), and/or take the stripe >> size of the underlying GEOM into account. This fundamentally >> doesn't change a thing for MBR, but has the side effect of >> achieving some of the goals *and* automatically works for >> EBR as well. >> >> Thus: rather than hack MBR and forgetting about EBR and other >> schemes, maybe we only have to tweak the geometry synthesis >> to give people what they want without going over board. > > I don't think that currently we do synthesize any geometry in kernel. > I think that we just whatever BIOS/firmware/etc provides to us in some way. Yes, we do. gpart makes sure that there's always a geometry and it adjusts the geometry based on information obtained from schemes. The geometry given by geom_disk (= ad or da) is typically the starting point. md does not have geometry information, causing certain tools to work less well. -- Marcel Moolenaar xcllnt@mac.com