From owner-freebsd-hackers@FreeBSD.ORG Thu Jun 28 19:49:31 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 34A15106564A; Thu, 28 Jun 2012 19:49:31 +0000 (UTC) (envelope-from alexander@leidinger.net) Received: from mail.ebusiness-leidinger.de (mail.ebusiness-leidinger.de [217.11.53.44]) by mx1.freebsd.org (Postfix) with ESMTP id B525B8FC17; Thu, 28 Jun 2012 19:49:30 +0000 (UTC) Received: from outgoing.leidinger.net (p5796C40B.dip.t-dialin.net [87.150.196.11]) by mail.ebusiness-leidinger.de (Postfix) with ESMTPSA id 97E3C8443FE; Thu, 28 Jun 2012 21:49:09 +0200 (CEST) Received: from unknown (IO.Leidinger.net [192.168.1.12]) by outgoing.leidinger.net (Postfix) with ESMTPS id F07C010A1; Thu, 28 Jun 2012 21:49:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=leidinger.net; s=outgoing-alex; t=1340912947; bh=Ry6lmCgOb82JHvW7IUERwucQLMP+5OvljheL+CMD+xk=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=fj7QcjBN38Xsu9MSMCP9wdPO5oBC0j9IBNq48PdVJusuzBjoM0vAfBdC//8rNT/Qf WpPtANKsxp1lX9Mn42v5QZApCiLEM47xO4XGMQ/e904h9I4bfg5FEACEmfoh2XZO68 0Xu04NpC6lqkVRcm4YXrypXji7Z0t2d1o6mog1TMoMKPv06rtZ+Os4vKziOmL55C78 wwl6a6FDwzgNZHk8fUjK4u32YpN1K9J0sdEnie5LQndjoVAeBTq+Twc17CgLHzoh9v XABEujhFb5b1KyAfgvqWMRGILHTAKv0DPQKb2GU2w9snXG1Dan6MYp2jhW6J0bC5Ob WvKqURoJ7dGVA== Date: Thu, 28 Jun 2012 21:49:02 +0200 From: Alexander Leidinger To: Marcel Moolenaar Message-ID: <20120628214902.00004e34@unknown> In-Reply-To: <8D85513D-CDFC-4D62-AA5A-F82F46E28CE5@xcllnt.net> References: <4FE9B01C.30306@yandex.ru> <201206270807.23347.jhb@freebsd.org> <4FEB0079.7050008@yandex.ru> <201206271028.54477.jhb@freebsd.org> <4FEB5A3C.5050900@borderworlds.dk> <1900D4C1-E5E5-446F-ABBF-976A2DFEB36B@xcllnt.net> <4FEC22A0.9000109@freebsd.org> <4FEC2D86.2040505@freebsd.org> <8D85513D-CDFC-4D62-AA5A-F82F46E28CE5@xcllnt.net> X-Mailer: Claws Mail 3.7.10cvs42 (GTK+ 2.16.6; i586-pc-mingw32msvc) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-EBL-MailScanner-Information: Please contact the ISP for more information X-EBL-MailScanner-ID: 97E3C8443FE.A49C0 X-EBL-MailScanner: Found to be clean X-EBL-MailScanner-SpamCheck: not spam, spamhaus-ZEN, SpamAssassin (not cached, score=-0.921, required 6, autolearn=disabled, ALL_TRUSTED -1.00, AWL 0.19, DKIM_SIGNED 0.10, DKIM_VALID -0.10, DKIM_VALID_AU -0.10, T_RP_MATCHES_RCVD -0.01) X-EBL-MailScanner-From: alexander@leidinger.net X-EBL-MailScanner-Watermark: 1341517751.24885@iNvizbqaG+q1nHn8i0eSQw X-EBL-Spam-Status: No X-Mailman-Approved-At: Thu, 28 Jun 2012 20:42:24 +0000 Cc: Doug Rabson , Moolenaar , Pawel Jakub Dawidek , Christian Laursen , freebsd-hackers , Marcel, Stefan Esser , Andriy Gapon , "Andrey V. Elsukov" , freebsd-current Subject: Re: [CFC/CFT] large changes in the loader(8) code X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jun 2012 19:49:31 -0000 On Thu, 28 Jun 2012 08:33:17 -0700 Marcel Moolenaar wrote: > My advise is to leave disk mirroring to H/W or firmware solutions and > use FreeBSD mirroring for FreeBSD partitions only. If you want to > mirror the whole disk, don't partition the disk with non-FreeBSD > partitioning schemes and partition only with FreeBSD-specific schemes > or put a FreeBSD file system on the whole disk. In other words: make > the whole disk private to FreeBSD. If I gmirror the entire disk, I already expressed my interest to make the whole disk private to FreeBSD, haven't I? Or are you suggesting to convince all BIOS vendors to include the ability to boot from some kind of FreeBSD private partitioning scheme (not MBR as it is not suitable, not GPT as you are not OK to use it on a gmirror)? > Whether or not people agree with this is besides the point. All I'm > saying is that unique disk identifiers such as the > "UniqueMBRSignature" (a 4 byte ID written at offset 440 in the MBR) > or the "DiskGUID" (an UUID written to offset 56 in the GPT header) > cannot, in general, be mirrored across disks if OSes can see the > mirrored disks as independent entities. One violates the spec on > grounds of making the *unique* disk identifier non-unique by > presenting OSes with multiple disks that have identical IDs. What about multipathing? In case the disk is attached via two paths but multipath is not enabled, the OS sees the same disk (and the same identical unique disk identifier) multiple times. Is this a violation of the spec too? Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137