From owner-freebsd-fs@FreeBSD.ORG Mon Aug 27 20:43:28 2007 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0911A16A417 for ; Mon, 27 Aug 2007 20:43:28 +0000 (UTC) (envelope-from cb@severious.net) Received: from ion.gank.org (ion.gank.org [69.55.238.164]) by mx1.freebsd.org (Postfix) with ESMTP id E8D2013C46C for ; Mon, 27 Aug 2007 20:43:27 +0000 (UTC) (envelope-from cb@severious.net) Received: by ion.gank.org (Postfix, from userid 1001) id D501511A7F; Mon, 27 Aug 2007 15:24:19 -0500 (CDT) Date: Mon, 27 Aug 2007 15:24:18 -0500 From: Craig Boston To: Simun Mikecin Message-ID: <20070827202418.GA71789@nowhere> Mail-Followup-To: Craig Boston , Simun Mikecin , freebsd-fs@freebsd.org References: <461381.93183.qm@web36609.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <461381.93183.qm@web36609.mail.mud.yahoo.com> User-Agent: Mutt/1.4.2.3i Cc: freebsd-fs@freebsd.org Subject: Re: zfs: Use wholedisk or not? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Aug 2007 20:43:28 -0000 On Mon, Aug 27, 2007 at 05:34:16AM -0700, Simun Mikecin wrote: > Is it safe to create zpool using whole disks instead of partitioning > (making a GPT partition)? It depends on what you mean by "safe". I have a couple of my machines set up that way without problems... > But I'm scared of what would happen if I plug such a disk on some > other machine, that runs some other OS (Windows for example) since > that disk will not have a valid MBR. ...however I haven't exposed the disks to a Windows monster^Wmachine to see if it eats them. > Will it try to restore a valid MBR and destroy a zpool in the process? I can't say with 100% certainty, but I think so long as you answer "no" to the prompt about writing a signature to the disk you'll be okay. > I know that using whole disks gives the benefit that zfs will to try > to enable disk write cache on it. FWIW, FreeBSD, unlike Solaris, always leaves the write cache enabled unless you explicitly turn it off, so there is no difference whether you're using a whole disk or an fdisk/gpt partition. Since device access is handled through GEOM, it may be impossible or at least difficult for ZFS to tell if what you put into the zpool is a physical disk or something else. Craig