From owner-freebsd-performance@FreeBSD.ORG Mon Sep 5 15:45:59 2005 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2FF2716A41F for ; Mon, 5 Sep 2005 15:45:59 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id CAF9543D48 for ; Mon, 5 Sep 2005 15:45:58 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id E7CBB5E96; Mon, 5 Sep 2005 11:45:57 -0400 (EDT) Received: from pi.codefab.com ([127.0.0.1]) by localhost (pi.codefab.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 89488-04; Mon, 5 Sep 2005 11:45:56 -0400 (EDT) Received: from [192.168.1.3] (pool-68-161-79-217.ny325.east.verizon.net [68.161.79.217]) by pi.codefab.com (Postfix) with ESMTP id 579485E18; Mon, 5 Sep 2005 11:45:56 -0400 (EDT) Message-ID: <431C683B.1080803@mac.com> Date: Mon, 05 Sep 2005 11:46:03 -0400 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.11) Gecko/20050801 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jeff Tchang References: <63f9d26505090417183dff415e@mail.gmail.com> In-Reply-To: <63f9d26505090417183dff415e@mail.gmail.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: amavisd-new at codefab.com Cc: freebsd-performance@freebsd.org Subject: Re: 3Ware 7500-4 Slow 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: Mon, 05 Sep 2005 15:45:59 -0000 Jeff Tchang wrote: [ ... ] > When I attempt to write many small files or remove a directory is when the > slowness kicks in. Is this just something due to Raid5? Here is the output > of Bonnie++: Small writes are pretty much the worst-case scenario for RAID-5, and it's normal to see a very significant performance drop-- by up to an order of magnitude-- from the performance of a bare drive. Good RAID controllers with lots of RAM can reduce the performance hit to perhaps less than a factor of 2. Choosing RAID-1 rather than RAID-5 for situations which are not read-only or read-mostly is probably a good idea. -- -Chuck