From owner-freebsd-questions@FreeBSD.ORG Mon Dec 2 17:46:58 2013 Return-Path: Delivered-To: freebsd-questions@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 BDAC692C for ; Mon, 2 Dec 2013 17:46:58 +0000 (UTC) Received: from mx02.qsc.de (mx02.qsc.de [213.148.130.14]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 7C67F17CF for ; Mon, 2 Dec 2013 17:46:58 +0000 (UTC) Received: from r56.edvax.de (port-92-195-106-241.dynamic.qsc.de [92.195.106.241]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx02.qsc.de (Postfix) with ESMTPS id F223E27793; Mon, 2 Dec 2013 18:46:56 +0100 (CET) Received: from r56.edvax.de (localhost [127.0.0.1]) by r56.edvax.de (8.14.5/8.14.5) with SMTP id rB2Hkgqm005466; Mon, 2 Dec 2013 18:46:42 +0100 (CET) (envelope-from freebsd@edvax.de) Date: Mon, 2 Dec 2013 18:46:42 +0100 From: Polytropon To: "Mike." Subject: Re: gmirror, gpart and MBR vs GPT in the Handbook Message-Id: <20131202184642.d35c4548.freebsd@edvax.de> In-Reply-To: <201312021235030914.007AF1DF@smtp.24cl.home> References: <201311301303210813.05DE187E@smtp.24cl.home> <201312011121580096.005D00FB@smtp.24cl.home> <201312021213320528.00673D5F@smtp.24cl.home> <20131202182623.43331984.freebsd@edvax.de> <201312021235030914.007AF1DF@smtp.24cl.home> Organization: EDVAX X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; i386-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list Reply-To: Polytropon List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Dec 2013 17:46:58 -0000 On Mon, 02 Dec 2013 12:35:03 -0500, Mike. wrote: > On 12/2/2013 at 6:26 PM Polytropon wrote: > > |On Mon, 02 Dec 2013 12:13:32 -0500, Mike. wrote: > |> My understanding is that MBR can be used with drives only up > to > |> and including 2TB in size. So if I use MBR, the maximum > drive > |> size I could use would be 2TB. Is that correct? > |[...] > |Regarding UFS's 2 TB limitation: > | > |http://www.freebsd.org/projects/bigdisk/ > | > |Additionally, MBR can be troublesome on bigger hard disks > |or stripes. > | > |http://www.freebsd.org/doc/handbook/bsdinstall-partitioning.html > > | > |Today's consensus seems to be: > | > |If you use ZFS, let ZFS deal with everything. > | > |If you use UFS, use gpart for preparation work. Use GPT when > |possible, MBR only in exceptions, and dedicated if and only > |if you really _really_ know what you're doing. :-) > ============= > > > Following the bsdinstall-partitioning link you cited, and then > following a link on that page, I wind up here: > > http://en.wikipedia.org/wiki/Master_boot_record > > which states: > > "...The organization of the partition table in the MBR limits > the maximum addressable storage space of a disk to 2 TB ...." > > > That (and other places) is where I got the 2TB limit of MBR into > my head. Am I misunderstanding that statement? I think you're correct regarding this finding: The data type 2^32 (because of 32 bit) defines the 2 TB limit. It applies both on MBR (which stores 32 bit values) and UFS (which also stores 32 bit values). However, I've never dealt with disks > 2 TB _and_ UFS before, so I can't add specific individual findings. :-) Again, consensus seems to be: If you have big disks, use ZFS. You use ZFS because the big disks are built into or attached to big computers with sufficient RAM, so it won't be a problem. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...