From owner-freebsd-questions@FreeBSD.ORG Thu Aug 3 14:35:48 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AA30416A4DF for ; Thu, 3 Aug 2006 14:35:48 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.FreeBSD.org (Postfix) with ESMTP id 65F1243D45 for ; Thu, 3 Aug 2006 14:35:48 +0000 (GMT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.13.1/8.13.4) id k73EZggd009093; Thu, 3 Aug 2006 09:35:42 -0500 (CDT) (envelope-from dan) Date: Thu, 3 Aug 2006 09:35:42 -0500 From: Dan Nelson To: Nikolas Britton Message-ID: <20060803143542.GA42319@dan.emsphone.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-OS: FreeBSD 5.5-PRERELEASE X-message-flag: Outlook Error User-Agent: Mutt/1.5.12-2006-07-14 Cc: freebsd-questions Subject: Re: Fastest disk in the west or bad iozone numbers? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Aug 2006 14:35:48 -0000 In the last episode (Aug 03), Nikolas Britton said: > Anyone have a clue why iozone reports disk read rates of 688 > MegaBytes/s on a 1GB test file? Am I doing something stupid, like not > converting the numbers correctly? You want to test using a file at least twice as big as your RAM, otherwise you're just testing your cache. You can see an example of this on the first graph at http://www.iozone.org . Only the far right edge shows the disks speed. web.archive.org shows that same image existed back in 2000 with a modtime of 1999, so it's possible the machine being tested had under 256MB of RAM. -- Dan Nelson dnelson@allantgroup.com