From owner-freebsd-stable@FreeBSD.ORG Tue Feb 16 15:56:54 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9BC091065676 for ; Tue, 16 Feb 2010 15:56:54 +0000 (UTC) (envelope-from peter@simons-rock.edu) Received: from hedwig.simons-rock.edu (hedwig.simons-rock.edu [208.81.88.14]) by mx1.freebsd.org (Postfix) with ESMTP id 5D0B68FC1F for ; Tue, 16 Feb 2010 15:56:54 +0000 (UTC) Received: from cesium.hyperfine.info (c2.8d.5646.static.theplanet.com [70.86.141.194]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by hedwig.simons-rock.edu (Postfix) with ESMTP id F35582BB343; Tue, 16 Feb 2010 10:56:52 -0500 (EST) Date: Tue, 16 Feb 2010 10:56:51 -0500 From: "Peter C. Lai" To: Artem Belevich Message-ID: <20100216155651.GI4648@cesium.hyperfine.info> References: <20100215090756.GA54764@icarus.home.lan> <20100215105000.101326yj01j0f64g@webmail.leidinger.net> <20100215122744.GA57382@icarus.home.lan> <20100215161105.14071eiflhc9le68@webmail.leidinger.net> <1140.69.37.94.221.1266256820.squirrel@lock.simons-rock.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Alexander Leidinger , freebsd-stable@freebsd.org, Jeremy Chadwick Subject: Re: hardware for home use large storage X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Feb 2010 15:56:54 -0000 On 2010-02-15 02:25:57PM -0800, Artem Belevich wrote: > > How much ram are you running with? > > 8GB on amd64. kmem_size=16G, zfs.arc_max=6G > > > In a latest test with 8.0-R on i386 with 2GB of ram, an install to a ZFS > > root *will* panic the kernel with kmem_size too small with default > > settings. Even dropping down to Cy Schubert's uber-small config will panic > > the kernel (vm.kmem_size_max = 330M, vfs.zfs.arc_size = 40M, > > vfs.zfs.vdev.cache_size = 5M); the system is currently stable using DIST > > kernel, vm.kmem_size/max = 512M, arc_size = 40M and vdev.cache_size = 5M. > > On i386 you don't really have much wiggle room. Your address space is > 32-bit and, to make things more interesting, it's split between > user-land and kernel. You can keep bumping KVA_PAGES only so far and > that's what limits your vm.kmem_size_max which is the upper limit for > vm.kmem_size. > > The bottom line -- if you're planning to use ZFS, do switch to amd64. > Even with only 2GB of physical RAM available, your box will behave > better. At the very least it will be possible to avoid the panics > caused by kmem exhaustion. > > --Artem Well this ZFS box (which admittedly is mostly a testbed) is only a lowly NetBurst Gallatin Xeon, pre-amd64 :( -- =========================================================== Peter C. Lai | Bard College at Simon's Rock Systems Administrator | 84 Alford Rd. Information Technology Svcs. | Gt. Barrington, MA 01230 USA peter AT simons-rock.edu | (413) 528-7428 ===========================================================