From owner-freebsd-stable@FreeBSD.ORG Fri Jul 25 04:30:01 2014 Return-Path: Delivered-To: freebsd-stable@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 25F8E7CA for ; Fri, 25 Jul 2014 04:30:01 +0000 (UTC) Received: from nahkohe.jetcafe.org (nahkohe.jetcafe.org [205.147.26.32]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id DF10A2E84 for ; Fri, 25 Jul 2014 04:30:00 +0000 (UTC) X-Envelope-To: freebsd-stable@freebsd.org Received: from [205.147.26.4] (hokkshideh.jetcafe.org [205.147.26.4]) by nahkohe.jetcafe.org (8.14.2/8.14.2) with ESMTP id s6P4TxXd083207 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 24 Jul 2014 21:29:59 -0700 (PDT) Message-ID: <53D1DD47.4040403@jetcafe.org> Date: Thu, 24 Jul 2014 21:29:59 -0700 From: Dave Hayes User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Warren Block Subject: Re: Gmirror + gpart corruption on 9.3-PRE References: <53D1BDB2.7030906@jetcafe.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 25 Jul 2014 04:30:01 -0000 On 07/24/2014 21:04, Warren Block wrote: > I believe that GPT tables somehow work only on the drive level. That > is, the GPT partitioning created inside the mirror actually overwrites > the existing one on the drive. As odd as it sounds, I think this is > intentional: GPT tables are only supposed to be at the beginning and end > of a physical drive. But I'm also not the one to explain it. > > However, the attempted GPT partitioning inside the mirrors is not needed > and can be left out. I did this because newfs seemed to corrupt the partition table if I did not do this. > GPT tests got more strict at some point. Maybe the rules for GPT tables > did also. That sounds like the simplest explanation. > For reference, here is my article on mirroring GPT disk partitions. I > do not recommend it. (Consider the head contention when multiple > mirrors on the same drive attempt to rebuild. Or disable automatic > rebuilding, but then it's going to be unpleasant in an emergency.) Since I'm only having two mirrors, would it be better to disable just the automatic rebuilding on the swap space? Would graid be better to use to achieve a mirrored volume? > For drives under 2TB, use MBR and bsdlabels, as ugly as it is. The > recently-rewritten Handbook procedure shows the right way to do it, > including alignment: > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/geom-mirror.html Yeah, I'd do this except there will come a day when 2TB drives cannot be found, and I have a significant history of having machines more than 6-7 years old. Sadly, I cannot use ZFS in this circumstance due to heavy memory requirements of what the machine will be used for. -- Dave Hayes - Consultant - Altadena CA, USA - dave@jetcafe.org >>>> *The opinions expressed above are entirely my own* <<<< There are only 10 kinds of people that understand binary - those that do, and those that don't.