From owner-freebsd-performance@FreeBSD.ORG Wed Jul 7 00:02:22 2010 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BDB311065672 for ; Wed, 7 Jul 2010 00:02:22 +0000 (UTC) (envelope-from ssanders@softhammer.net) Received: from oproxy2-pub.bluehost.com (oproxy2-pub.bluehost.com [67.222.39.60]) by mx1.freebsd.org (Postfix) with SMTP id 78AAC8FC14 for ; Wed, 7 Jul 2010 00:02:22 +0000 (UTC) Received: (qmail 32176 invoked by uid 0); 6 Jul 2010 23:35:42 -0000 Received: from unknown (HELO host358.hostmonster.com) (66.147.240.158) by oproxy2.bluehost.com with SMTP; 6 Jul 2010 23:35:42 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=softhammer.net; h=Received:Message-ID:Date:From:User-Agent:MIME-Version:To:Subject:X-Enigmail-Version:Content-Type:Content-Transfer-Encoding:X-Identified-User; b=CBTSshpQMZAW66LOykfUN98Tjt8pn+JueuO4tuLmW9eSTX0JmF4uKCzGHxA3v/sCwfPG6DgAXgErqSr1nm5tENx/CsfZELZNZpdb8+928lvV1hhj4ZHHECNI0DZuKckV; Received: from pool-74-96-233-244.washdc.fios.verizon.net ([74.96.233.244] helo=onyx.softhammer.net) by host358.hostmonster.com with esmtpa (Exim 4.69) (envelope-from ) id 1OWHfx-0003FF-N0 for freebsd-performance@freebsd.org; Tue, 06 Jul 2010 17:35:41 -0600 Message-ID: <4C33BDCC.1020004@softhammer.net> Date: Tue, 06 Jul 2010 19:35:40 -0400 From: Stephen Sanders User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 MIME-Version: 1.0 To: freebsd-performance@freebsd.org X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Identified-User: {2492:host358.hostmonster.com:softhamm:softhammer.net} {sentby:smtp auth 74.96.233.244 authed with ssanders@softhammer.net} Subject: More Controllers != Higher Through Put X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Jul 2010 00:02:22 -0000 I'm wondering if anyone has heard of this. I've a system with a 3ware 9650 servicing 4 7200RPM Segate 1TB drives and the motherboard servicing 2 7200 RPM Segate 1TB drives. The 4 disk array is RAID 6 while the 2 disk array is RAID 1. The drives should deliver about 100MB/s. 1. The most the 4 disk array is developing is 250MB/s write performance while the 2 disk array is coming in at 90MB/s write performance. The 4 disk array seems slow. 2. Attempting to write to both arrays simultaneously causes the rate on the 4 disk array to drop to 150MB/s and the 2 disk array drops to 60MB/s I'd expect the 4 disk array should look more like 300+MB/s while the 2 disk array is about right. I don't get why there should be a 'coupling' between the rates on separate controllers. The system is running FreeBSD 8.0, has 16GB of RAM in the system, and the test program is using O_DIRECT for writes in order to avoid the page daemon. Thanks