From owner-freebsd-fs@FreeBSD.ORG Wed Mar 2 12:16:14 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 B3CCC106566B for ; Wed, 2 Mar 2011 12:16:14 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta05.emeryville.ca.mail.comcast.net (qmta05.emeryville.ca.mail.comcast.net [76.96.30.48]) by mx1.freebsd.org (Postfix) with ESMTP id 928798FC12 for ; Wed, 2 Mar 2011 12:16:14 +0000 (UTC) Received: from omta24.emeryville.ca.mail.comcast.net ([76.96.30.92]) by qmta05.emeryville.ca.mail.comcast.net with comcast id EC1x1g0021zF43QA5CGEgv; Wed, 02 Mar 2011 12:16:14 +0000 Received: from koitsu.dyndns.org ([98.248.33.18]) by omta24.emeryville.ca.mail.comcast.net with comcast id ECGC1g0060PUQVN8kCGCFn; Wed, 02 Mar 2011 12:16:13 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id 414169B422; Wed, 2 Mar 2011 04:16:12 -0800 (PST) Date: Wed, 2 Mar 2011 04:16:12 -0800 From: Jeremy Chadwick To: Dr Josef Karthauser Message-ID: <20110302121612.GA61020@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> <20110302001650.GB49147@icarus.home.lan> <27423168-85BE-41B1-8E14-94F01310EFE4@tao.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27423168-85BE-41B1-8E14-94F01310EFE4@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 12:16:14 -0000 On Wed, Mar 02, 2011 at 10:28:50AM +0000, Dr Josef Karthauser wrote: > On 2 Mar 2011, at 00:16, Jeremy Chadwick wrote: > > > 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. > > I guess I should have been a bit clearer, I mean without any external > devices backing them. Seeing as this is to be running on a VPS/Xen at > a hosting environment I'm not able to add any additional devices. I'm > not memory starved however. Is it madness to use a memory disk? (The > instance in question will have 6gb of ram total to play with.). Again: don't disable the ZIL, and adjust the ARC to whatever size you want using a combo of vm.kmem_size and vfs.zfs.arc_max. Make use of the RAM you have available to you. :-) -- | 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 |