From owner-freebsd-fs@FreeBSD.ORG Wed Mar 2 00:16:58 2011 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 D7CC41065672 for ; Wed, 2 Mar 2011 00:16:58 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta06.emeryville.ca.mail.comcast.net (qmta06.emeryville.ca.mail.comcast.net [76.96.30.56]) by mx1.freebsd.org (Postfix) with ESMTP id B824D8FC13 for ; Wed, 2 Mar 2011 00:16:58 +0000 (UTC) Received: from omta18.emeryville.ca.mail.comcast.net ([76.96.30.74]) by qmta06.emeryville.ca.mail.comcast.net with comcast id E0Ek1g0071bwxycA60GyE9; Wed, 02 Mar 2011 00:16:58 +0000 Received: from koitsu.dyndns.org ([98.248.33.18]) by omta18.emeryville.ca.mail.comcast.net with comcast id E0Gq1g0190PUQVN8e0GtjV; Wed, 02 Mar 2011 00:16:56 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id BC83C9B422; Tue, 1 Mar 2011 16:16:50 -0800 (PST) Date: Tue, 1 Mar 2011 16:16:50 -0800 From: Jeremy Chadwick To: Dr Josef Karthauser Message-ID: <20110302001650.GB49147@icarus.home.lan> References: <0E00DAFC-C39F-47DC-B9AF-16419C20997F@tao.org.uk> <615F1346-E830-42E2-B229-4181B8BC56BD@exonetric.com> <53FA69D2-2EF0-4CBF-985B-6E710F15FE02@tao.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53FA69D2-2EF0-4CBF-985B-6E710F15FE02@tao.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-fs@freebsd.org Subject: Re: ZFS on a single disk? 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: Wed, 02 Mar 2011 00:16:58 -0000 On Wed, Mar 02, 2011 at 12:00:24AM +0000, Dr Josef Karthauser wrote: > On 1 Mar 2011, at 23:49, Mark Blackman wrote: > > > > On 1 Mar 2011, at 23:27, Dr Josef Karthauser wrote: > > > >> Does it make sense to run zfs on a single disk? > >> > >> I'm setting up a FreeBSD host over at a Xen provider, with a single 80GB disk image. Ideally I'd like to run ZFS on this system, for snapshot and flexible creation of filesystems and quotas. Has anyone got any recommendations for me in this regard? Am I crazy? > > > > Not crazy, I do this as well, all the time just to get the management capabilities and > > leave hardware RAID to manage the availability. > > > > - Mark > > Any idea what the performance implications are? Can I get away without a ZIL or ARC and still get a decent performance? Do not disable the ZIL. I hate referring to the Solaris documentation for FreeBSD, but it applies: http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Disabling_the_ZIL_.28Don.27t.29 And you cannot disable the ARC, so just tune it appropriately (which you'll need to do on FreeBSD anyway). In fact, by getting rid of the ARC (as you proposed), you would suffer worse performance than if you had it in use. -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP 4BD6C0CB |