From owner-freebsd-cluster@FreeBSD.ORG Mon Apr 5 01:24:28 2004 Return-Path: Delivered-To: freebsd-cluster@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3042F16A4CE for ; Mon, 5 Apr 2004 01:24:28 -0700 (PDT) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.185]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5C29243D4C for ; Mon, 5 Apr 2004 01:24:27 -0700 (PDT) (envelope-from sporner@nentec.de) Received: from [212.227.126.161] (helo=mrelayng.kundenserver.de) by moutng.kundenserver.de with esmtp (Exim 3.35 #1) id 1BAPP7-0000YK-00; Mon, 05 Apr 2004 10:24:25 +0200 Received: from [194.25.215.66] (helo=gate.nentec.de) (TLSv1:EDH-RSA-DES-CBC3-SHA:168) (Exim 3.35 #1) id 1BAPP6-0001je-00; Mon, 05 Apr 2004 10:24:25 +0200 Received: from nenny.nentec.de (nenny.nentec.de [153.92.64.1]) by gate.nentec.de (8.11.3/) with ESMTP id i358OMq26791; Mon, 5 Apr 2004 10:24:22 +0200 Received: from nentec.de (andromeda.nentec.de [153.92.64.34]) by nenny.nentec.de (8.11.3/8.11.3) with ESMTP id i358OKN23221; Mon, 5 Apr 2004 10:24:21 +0200 Message-ID: <407117B4.2000800@nentec.de> Date: Mon, 05 Apr 2004 10:24:20 +0200 From: Andy Sporner User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2a) Gecko/20020910 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Michael McDonald References: <002401c419e7$76692ac0$2f01a8c0@MICHAELIWZHLNY> <20040404113055.GA2677@ipx20050.ipxserver.de> <002c01c41aa5$1fbd6b50$2f01a8c0@MICHAELIWZHLNY> Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: by AMaViS-perl11-milter (http://amavis.org/) X-Provags-ID: kundenserver.de abuse@kundenserver.de auth:56ea142331898a06f3703ddc80e12bc5 cc: freebsd-cluster@freebsd.org Subject: Re: Request for Cluster Recommendations X-BeenThere: freebsd-cluster@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Clustering FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 05 Apr 2004 08:24:28 -0000 Hi Michael, >For the most part, my codes have been data >parallel and have invlolved broadcasting >parameters and merging results at the end of >distributed serial computations. They have >involved many evaluations of small matrices >and data sets and I get better speedups with >simultaneous serial executions. Much of the >work I'm looking towards would make use >of a grid approach in the style of seti@home >or the factoring projects. > > Seti@home is very nice indeed. I am a participant as well (Captain Blank) >I would expect bursts of communication >separated by periods of computation; >Overall, communication wouldn't be >so much of a bottleneck, but I'd like it >to be fast when it does occur. If Andy >Sporner's 30% figure holds up, I think >local disks as buffers would allow the >network access to be smeared out. I've got >40% in mind as an upper performance limit >for ethernet due to collisions, but I can't back >that up. Local buffers seem to allow for >scheduling comm. so as to avoid collisions. > With a switch you wouldn't normally have enough collisions to worry about, unless you approach the bandwidth of the media. When I spoke of the 30% I was refering to a extended burst. We benchmark our firewall loadbalancer(nitro) with 4 firewalls and a traffic generation farm for entire weekends for reliability testing, this is where I observed this value. The Firewall machines are 2.8 Ghz Athlon servers. > >Starting out with 100Mbit may make sense as >a cheaper/simpler startup - no NIC >purchases. After running some simulation >and benchmarking with the apps, upgrading to Gigabit wouldn't be an undue burden. > That's not a bad idea, but many of the 1U servers (not to mention the better motherboards (such as ASUS) are with GB as standard). The switch is a little more expensive, but not that drastic. >Some initial attempts at estimating >communication & compute demands would >be in order. Aside from the fiber options, is the cabling the same for 100Mbit and Gbit? > Using Cat6 -- yes, but we have also used cat 5 with some success. If you start wth CAT-6 you will always win. Good luck! Andy