From owner-freebsd-stable@FreeBSD.ORG Mon Feb 15 22:25:58 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 9C515106566C for ; Mon, 15 Feb 2010 22:25:58 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-iw0-f175.google.com (mail-iw0-f175.google.com [209.85.223.175]) by mx1.freebsd.org (Postfix) with ESMTP id 5BD8C8FC12 for ; Mon, 15 Feb 2010 22:25:58 +0000 (UTC) Received: by iwn5 with SMTP id 5so2204357iwn.9 for ; Mon, 15 Feb 2010 14:25:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to:cc :content-type; bh=AHZ814NXUXCPg/nLvGFIyAivcqDaDU7aen4+RsqLibo=; b=FDmVULoUjtdaIRSTNDcMhLo7CplmWla3pP2a8Ao7DgY/m/jXiQDyXvYJdvtmcLsFq3 qLBHoVhygyHGk/kAxZs9YYLsuthw0RjiYkpLOA4upGc5Wnv1dDMshb02+Wh7bhJ65oZ6 CxsGQx97sP8y75z4VKBZIv6etFIGv6ZqqP+Hs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; b=T1/ayhWQ4bfAvRTyEa4hPXl3jXYn82GjxR44G7cUhzZFvSJSEABNY95+hRYCQi37Ke sw0iXcmNo4oh9EF5AZi97Ugho2bdt4Tmei9jvDP4Cudo7nC/aCX73bNdUZVGvQQ06GYe xi3pIxoccVuCV3K1EeqeXqrAS5n0TYexnILqo= MIME-Version: 1.0 Sender: artemb@gmail.com Received: by 10.231.147.148 with SMTP id l20mr1319405ibv.77.1266272757671; Mon, 15 Feb 2010 14:25:57 -0800 (PST) In-Reply-To: <1140.69.37.94.221.1266256820.squirrel@lock.simons-rock.edu> 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> Date: Mon, 15 Feb 2010 14:25:57 -0800 X-Google-Sender-Auth: bf16b9fa9d6878d3 Message-ID: From: Artem Belevich To: "Peter C. Lai" Content-Type: text/plain; charset=ISO-8859-1 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: Mon, 15 Feb 2010 22:25:58 -0000 > 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