From owner-freebsd-questions@freebsd.org Wed Aug 30 14:56:53 2017 Return-Path: Delivered-To: freebsd-questions@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 08799E03BFE for ; Wed, 30 Aug 2017 14:56:53 +0000 (UTC) (envelope-from mikhailg@webanoide.org) Received: from msa.san.navalradio.net (msa.san.navalradio.net [206.251.255.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E548070029 for ; Wed, 30 Aug 2017 14:56:51 +0000 (UTC) (envelope-from mikhailg@webanoide.org) Received: from [192.168.0.121] ([172.18.128.200]) (authenticated bits=0) by msa.san.navalradio.net (8.15.2/8.15.2) with ESMTPA id v7UEtbt6043390 for ; Wed, 30 Aug 2017 14:55:39 GMT (envelope-from mikhailg@webanoide.org) X-Authentication-Warning: msa.san.navalradio.net: Host [172.18.128.200] claimed to be [192.168.0.121] Subject: Re: help creating new gmirror > 2TB To: freebsd-questions@freebsd.org References: From: Mikhail Goriachev Message-ID: <2eeddc7e-e5ba-5a57-b40f-2cd4ca892494@webanoide.org> Date: Wed, 30 Aug 2017 11:56:42 -0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 30 Aug 2017 14:56:53 -0000 On 29/08/2017 17:12, William Dudley wrote: > Hi, > > I want to create a simple mirror > 2TB on a FreeBSD 10.3 system. > > I have 2 identical 4TB disks. > > The examples in freebsd handbook "geom-mirror" pages show creation of a 2TB > mirror using > MBR partitioning, and that has an upper limit of 2TB. > > Some documentation says not to use GPT partitioning with gmirror because > both store their information in the last sector on the disk. > > I'm not expert enough to be able to solve this myself. > > How do I create a gmirror of 4TB size? > > I want to partition it into 4 slices after I create it, but think I can use > gpart to do that. > > Note: I'm not interested in using zfs unless there's no way to do this with > gmirror. > I read too many zfs failure stories on this mailing list to be comfortable > with zfs. > > Thanks in advance, > Bill Dudley Hi Bill, Great articles that helped me a lot back awhile: http://www.wonkity.com/~wblock/docs/html/disksetup.html http://www.wonkity.com/~wblock/docs/html/gmirror.html In regard with disk thrashing, just mirror one essential partition. IMO thrashing isn't that bad if it happens once or twice a year... but it takes a long time and the disks go nuts. GPT is the way to go in your situation. Cheers, Mikhail. -- Mikhail Goriachev Webanoide