From owner-freebsd-questions@FreeBSD.ORG Mon Dec 2 17:26:47 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 4F867AF8 for ; Mon, 2 Dec 2013 17:26:47 +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 0FAE41650 for ; Mon, 2 Dec 2013 17:26:46 +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 83638278AA; Mon, 2 Dec 2013 18:26:38 +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 rB2HQNWf005406; Mon, 2 Dec 2013 18:26:23 +0100 (CET) (envelope-from freebsd@edvax.de) Date: Mon, 2 Dec 2013 18:26:23 +0100 From: Polytropon To: "Mike." Subject: Re: gmirror, gpart and MBR vs GPT in the Handbook Message-Id: <20131202182623.43331984.freebsd@edvax.de> In-Reply-To: <201312021213320528.00673D5F@smtp.24cl.home> References: <201311301303210813.05DE187E@smtp.24cl.home> <201312011121580096.005D00FB@smtp.24cl.home> <201312021213320528.00673D5F@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 17:26:47 -0000 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? Don't confuse partitioning schemes and file systems. Both are different things, happening on different "layers". To make it simpler than it probably is: Partitioning = a) MBR with classic tools (fdisk, bsdlabel) b) MBR with modern tool (gpart) c) GPT (gpart) d) Dedicated (only the "bsdlabel part") RAID concepts = a) mirror b) stripe c) combined and extended forms ... File system = a) UFS option +U: soft updates option +J: journal b) ZFS Of course ZFS can handle things like "RAID concepts" already internally, whereas UFS would use gstripe and gmirror as "little helpers" - it will run on top of them, i. e., you initialize the device that represents the whole mirror instead of individually dealing with the drives that the mirror is constructed of. 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. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...