From owner-freebsd-stable@FreeBSD.ORG Fri Sep 26 16:13:54 2008 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 0345D1065696; Fri, 26 Sep 2008 16:13:54 +0000 (UTC) (envelope-from bkelly@vadev.org) Received: from ianto.vadev.org (vadev.org [66.92.166.151]) by mx1.freebsd.org (Postfix) with ESMTP id 81F3A8FC12; Fri, 26 Sep 2008 16:13:53 +0000 (UTC) (envelope-from bkelly@vadev.org) Received: from harkness.vadev.org (harkness.vadev.org [192.168.1.210]) (authenticated bits=0) by ianto.vadev.org (8.14.3/8.14.3) with ESMTP id m8QFq88Z093585 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Fri, 26 Sep 2008 15:52:09 GMT (envelope-from bkelly@vadev.org) Message-Id: From: Ben Kelly To: Bartosz Stec In-Reply-To: <48DCA0AF.5050000@kkip.pl> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v929.2) Date: Fri, 26 Sep 2008 11:52:08 -0400 References: <48DB6772.1060400@kkip.pl> <20080925130227.GA13497@icarus.home.lan> <48DB9CAA.9060807@kkip.pl> <20080925145154.GA15486@icarus.home.lan> <48DCA0AF.5050000@kkip.pl> X-Mailer: Apple Mail (2.929.2) X-Spam-Score: 0.01 () ALL_TRUSTED,AWL X-Scanned-By: MIMEDefang 2.64 on 192.168.1.110 Cc: Jeremy Chadwick , freebsd-stable@freebsd.org Subject: Re: vm.kmem_size settings doesn't affect loader? 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: Fri, 26 Sep 2008 16:13:54 -0000 On Sep 26, 2008, at 4:43 AM, Bartosz Stec wrote: > Jeremy Chadwick wrote: >> >> These are the tuning settings I use: >> >> vm.kmem_size="1536M" >> vm.kmem_size_max="1536M" >> vfs.zfs.arc_min="16M" >> vfs.zfs.arc_max="64M" >> > Yesterday I've added 512 MB memory to box (sum 1,5GB), and set > vm.kmem_size and vm.kmem_size to "1024M". With pieces of 1024MB, > 512MB, 256MB, 256MB available and 3 memory slots it is hard to have > 2GB RAM ;) > Until now it survived world cleaning/building/installing/bonnie++ > benchmarkink/fs scrubing and general usage. Memory usage seems > stable. If unfortunately kmem exhaustion will happen again I will > experiment with ARC settings. > IMHO you've explained gently a lot of zfs tuning concerns in this > thread and they should be added to tuning guide - espacially > explanation of ARC and prefetch settings. Thanks again! Did you increase KVA_PAGES in your kernel config as well? The default of 256 only allows 1GB of kernel memory total. Setting KVA_PAGES to 384 would probably be good for a kmem_size of 1GB. This would give leave you with 512MB of space for other things in the kernel. In your kernel config: options KVA_PAGES=384 Sorry if you already knew this. I know its in the zfs tuning guide. I just hadn't seen it mentioned in the thread yet and wanted to make sure it wasn't missed. Hope that helps. - Ben