From owner-freebsd-fs@FreeBSD.ORG Tue Jun 1 19:54:42 2010 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 1CD86106566C for ; Tue, 1 Jun 2010 19:54:42 +0000 (UTC) (envelope-from korvus@comcast.net) Received: from mx04.pub.collaborativefusion.com (mx04.pub.collaborativefusion.com [206.210.72.84]) by mx1.freebsd.org (Postfix) with ESMTP id D96628FC12 for ; Tue, 1 Jun 2010 19:54:41 +0000 (UTC) Received: from [192.168.2.164] ([206.210.89.202]) by mx04.pub.collaborativefusion.com (StrongMail Enterprise 4.1.1.4(4.1.1.4-47689)); Tue, 01 Jun 2010 15:56:03 -0400 X-VirtualServerGroup: Default X-MailingID: 00000::00000::00000::00000::::1379 X-SMHeaderMap: mid="X-MailingID" X-Destination-ID: freebsd-fs@freebsd.org X-SMFBL: ZnJlZWJzZC1mc0BmcmVlYnNkLm9yZw== Message-ID: <4C05657A.7060900@comcast.net> Date: Tue, 01 Jun 2010 15:54:34 -0400 From: Steve Polyack User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.9.1.7) Gecko/20100311 Thunderbird/3.0.1 MIME-Version: 1.0 To: Darren Pilgrim References: <060401cafe37$a411b240$ec3516c0$@net> <4BFF894F.4010008@icyb.net.ua> <20100528134549.GA75411@icarus.home.lan> <4C05577F.7040001@bitfreak.org> In-Reply-To: <4C05577F.7040001@bitfreak.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: amd64@freebsd.org, freebsd-fs@freebsd.org Subject: Re: FreeBSD 8.1-Prerelease Panic amd64 w/ZFS.. 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: Tue, 01 Jun 2010 19:54:42 -0000 On 06/01/10 14:54, Darren Pilgrim wrote: > Jeremy Chadwick wrote: >> To the OP: you will need to increase vm.kmem_size in /boot/loader.conf >> and reboot the system. "What value do I pick?" With 4GB, I would >> recommend you use these two variables: >> >> vm.kmem_size="2048M" >> vfs.zfs.arc_max="1536M" >> >> This will increase the available kmem, and also limit the ARC size >> explicitly to nothing larger than 1.5GB. This should stabilise your >> system. > > What are the general guidelines for sizing these given the amount of > physical RAM? For example, I have a machine with 6 GB, so I have: > > vm.kmem_size="3072M" > vfs.zfs.arc_max="2048M" > Things may have changed, but I would recommend 'vm.kmem_size="9G"' (1.5x physical memory size) and an ARC max of 3GB (half memory size). If you are doing more than just serving ZFS on the box, you may want to keep the ARC max around 2GB or less to leave some for other applications. The vm.kmem_size recommendation is based on a a good bit of list reading I did several months ago when setting my ZFS system up. That machine has made it over 6 months of production usage without a crash while serving a few terabytes of data to various NFS clients. It has 8GB of physical RAM, a vm.kmem_size of 12G, and a vfs.zfs.arc_max of 4G. It's been running 8-STABLE since 03/24/2010. Side note: Jeremy's values may work great, but these are the values I've been using myself and have not had a single problem. ZFS rocks. Steve