From owner-freebsd-fs@FreeBSD.ORG Fri Mar 4 14:06:29 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 485DD106566B for ; Fri, 4 Mar 2011 14:06:29 +0000 (UTC) (envelope-from joe@tao.org.uk) Received: from alpha.tao.org.uk (alpha.tao.org.uk [212.42.1.232]) by mx1.freebsd.org (Postfix) with ESMTP id 05D078FC13 for ; Fri, 4 Mar 2011 14:06:28 +0000 (UTC) Received: from localhost (alpha.tao.org.uk [212.42.1.232]) by alpha.tao.org.uk (Postfix) with ESMTP id D9F161076C85; Fri, 4 Mar 2011 14:06:27 +0000 (GMT) Received: from alpha.tao.org.uk ([212.42.1.232]) by localhost (mail.tao.org.uk [212.42.1.232]) (amavisd-maia, port 10024) with LMTP id 82437-06; Fri, 4 Mar 2011 14:06:16 +0000 (GMT) Received: from [90.155.77.76] (unknown [90.155.77.76]) (Authenticated sender: joemail@alpha.tao.org.uk) by alpha.tao.org.uk (Postfix) with ESMTPA id C0AEA1076C76; Fri, 4 Mar 2011 14:06:13 +0000 (GMT) Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii From: Dr Josef Karthauser In-Reply-To: <20110304140015.GA27523@icarus.home.lan> Date: Fri, 4 Mar 2011 14:06:12 +0000 Content-Transfer-Encoding: 7bit Message-Id: 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> <20110302121612.GA61020@icarus.home.lan> <9EAE56CB-0CE9-4A08-B783-3EF9B1059E62@tao.org.uk> <20110304131849.GA26774@icarus.home.lan> <0A0632A0-24C3-4B11-8542-37A58DCA6390@tao.org.uk> <20110304140015.GA27523@icarus.home.lan> To: Jeremy Chadwick X-Mailer: Apple Mail (2.1081) X-Virus-Scanned: Maia Mailguard 1.0.2a Cc: Tom Evans , 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: Fri, 04 Mar 2011 14:06:29 -0000 On 4 Mar 2011, at 14:00, Jeremy Chadwick wrote: > On Fri, Mar 04, 2011 at 01:49:15PM +0000, Dr Josef Karthauser wrote: >> I don't believe that that's an issue anymore. The XEN kernel comes >> configured with PAE as a default option, and I've seen elsewhere that >> there is no technical problems running ZFS in a PAE environment. (The >> PAE docs are out of date when they say we can't use kernel modules, >> and any 64 bit aware kernel model should run with PAE with no >> difficulties). > > XEN isn't something I'm familiar with, which is obviously a huge part of > the problem with me trying to give you advice on the matter. :-) The > only virtualisation "system" I'm familiar with is VMware Workstation, > which isn't anything like XEN. > > What I'm going off of is /sys/i386/conf/PAE vs. /sys/i386/conf/XEN. > > Be sure to notice all the "nodevice" lines in /sys/i386/conf/PAE, and > the comment directly above those. The XEN configuration file has > "options PAE", which is ultimately what a driver/piece of kernel code > would use for compile-time detection for supporting/working under PAE. > > For example, arcmsr(4) will flat out panic() (intentionally) if PAE > is used. bge(4) and twa(4) appear to have a 4GB boundary on DMA; I > don't know the implications of this. Luckily I care not about device support. As long as the paravirtualised devices work, and zfs works, I need nothing else. So, I guess the zfs question boils down to whether (given everything else being equal with PAE support) I could consider zfs on i386 with a PAE memory model to be stable enough for a production server (on 8.2). Joe