From owner-freebsd-hackers@FreeBSD.ORG Sun Jun 1 14:36:27 2014 Return-Path: Delivered-To: hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 46DB5E6B; Sun, 1 Jun 2014 14:36:27 +0000 (UTC) Received: from wonkity.com (wonkity.com [67.158.26.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "wonkity.com", Issuer "wonkity.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id CED272196; Sun, 1 Jun 2014 14:36:26 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.8/8.14.8) with ESMTP id s51EaO7w024363 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sun, 1 Jun 2014 08:36:24 -0600 (MDT) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.8/8.14.8/Submit) with ESMTP id s51EaO5m024360; Sun, 1 Jun 2014 08:36:24 -0600 (MDT) (envelope-from wblock@wonkity.com) Date: Sun, 1 Jun 2014 08:36:24 -0600 (MDT) From: Warren Block To: Ian Lepore Subject: Re: fdisk(8) vs gpart(8), and gnop In-Reply-To: <1401632369.20883.51.camel@revolution.hippie.lan> Message-ID: References: <20140601004242.GA97224@bewilderbeast.blackhelicopters.org> <20140601020053.GR43976@funkthat.com> <1401632369.20883.51.camel@revolution.hippie.lan> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (wonkity.com [127.0.0.1]); Sun, 01 Jun 2014 08:36:24 -0600 (MDT) Cc: John-Mark Gurney , hackers@FreeBSD.org, "Michael W. Lucas" X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 Jun 2014 14:36:27 -0000 On Sun, 1 Jun 2014, Ian Lepore wrote: > On Sat, 2014-05-31 at 19:00 -0700, John-Mark Gurney wrote: >> Michael W. Lucas wrote this message on Sat, May 31, 2014 at 20:42 -0400: >>> $SUBJECT have been two contentious points of discussion in private >>> mail, Twitter, the BSDCan bar track, and random people passing on the >>> street. I was very surprised at the number of knowledgeable people who >>> have different ideas on this and argue about it at length. >>> >>> I'm hoping to verify what seems to be correct. >>> >>> First, is fdisk EVER necessary? I *believe* that gpart's '-a 4k' >>> handles all alignment issues for the 512B/4KB sector issues. If you >> >> gpart's -a will not properly align MBR's slices due to enforced CHS... > > Maybe this is naive, but... can't we just *fix* that? Thread starts here: http://lists.freebsd.org/pipermail/freebsd-geom/2014-February/005835.html > For the longest time geom would warn about "geometry does not match > label" that had something to do with different parts of the code > calculating different CHS values. Eventually it was decided to remove > the unactionable message, and my vague memory is that the justification > was basically "because CHS is meaningless to geom and modern BIOSen." > > If there's some "it would cause problems on this ancient hardware that > only 3 people in the world use" (I'm usually one of those people -- we > support some old equipment in the field at $work), then maybe there > could be a flag that enables the old CHS alignment behavior. Short form of above: gpart is supposed to hide and handle underlying GEOM issues, so it needs an override to be able to create these "non-standard" MBRs with slices aligned to arbitrary values.