From owner-freebsd-hackers@freebsd.org Tue Jan 31 16:21:58 2017 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5ADE0CCA0AD for ; Tue, 31 Jan 2017 16:21:58 +0000 (UTC) (envelope-from bu7cher@yandex.ru) Received: from forward4p.cmail.yandex.net (forward4p.cmail.yandex.net [IPv6:2a02:6b8:0:1465::14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "forwards.mail.yandex.net", Issuer "Yandex CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 159B51DB5 for ; Tue, 31 Jan 2017 16:21:58 +0000 (UTC) (envelope-from bu7cher@yandex.ru) Received: from smtp2h.mail.yandex.net (smtp2h.mail.yandex.net [84.201.187.145]) by forward4p.cmail.yandex.net (Yandex) with ESMTP id D706920C9C; Tue, 31 Jan 2017 19:21:54 +0300 (MSK) Received: from smtp2h.mail.yandex.net (localhost.localdomain [127.0.0.1]) by smtp2h.mail.yandex.net (Yandex) with ESMTP id 7FB387809DB; Tue, 31 Jan 2017 19:21:51 +0300 (MSK) Received: by smtp2h.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id CJEGG6GHcK-LpjWlSqO; Tue, 31 Jan 2017 19:21:51 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1485879711; bh=uA86gC+Hyf1bZAyq4Rouz8/zXCm4D7w6srDLuQrplMs=; h=Subject:To:References:Cc:From:Message-ID:Date:In-Reply-To; b=Uu3ZOOP4n447WBxjSRnhrKq2MEB7Ei8dzGLdVUgpexkCJt04YYmdGZtypD+WTIRQS jPMmP/vuEWV5Ueh1BEQMPXkPQPfdlWC5JHC+B7q3hmISN7JVim7jWGSg2UtHyyDYLq uENxhZj9P4CO70CB1KQ4FZz2aIwmxRGfv/kmHKuc= Authentication-Results: smtp2h.mail.yandex.net; dkim=pass header.i=@yandex.ru X-Yandex-Suid-Status: 1 0,1 0,1 0,1 0 Subject: Re: How to safely remove rest of GTP? To: "Rodney W. Grimes" , Warren Block References: <201701311543.v0VFh0Bl044986@pdx.rh.CN85.dnsmgr.net> Cc: freebsd-hackers@freebsd.org, Slawa Olhovchenkov From: "Andrey V. Elsukov" Message-ID: <515e709a-5c34-0bc1-bc3b-7cff99f6dd97@yandex.ru> Date: Tue, 31 Jan 2017 19:20:36 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <201701311543.v0VFh0Bl044986@pdx.rh.CN85.dnsmgr.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Jan 2017 16:21:58 -0000 On 31.01.2017 18:43, Rodney W. Grimes wrote: > ... much deleted ... >> >>> It is impossible to have a corrupted GPT and some >>> other type of partition table in the same time. > > I believe that statement is in error. > dd if=/boot/boot0 of=/dev/ada0 > Would not that lead to this very situation if done > to a GPT parted disk drive? No, it will not lead to this situation. /boot/boot0 is similar to /boot/mbr in the example, and with /dev/ada0 all will behaves like with /dev/md0. >> Maybe when only using FreeBSD and gpart, but I'm pretty sure I've seen >> forum users who have tried some crappy other formatting tool and have >> overwritten the primary GPT with a valid MBR and left the secondary GPT >> untouched. This only becomes obvious when they bring the disk back to a >> FreeBSD system. > > As almost all MBR tools are un aware of GPT so well not do anything to > destroy the secondary GPT, so this is infact very likely to occur. Please, give me some working example, when or where you have a problem, and not some theoretical, based on previous negative experience or memories. -- WBR, Andrey V. Elsukov