From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267218AbUBMWnA (ORCPT ); Fri, 13 Feb 2004 17:43:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267256AbUBMWm6 (ORCPT ); Fri, 13 Feb 2004 17:42:58 -0500 Received: from willy.net1.nerim.net ([62.212.114.60]:1550 "EHLO willy.net1.nerim.net") by vger.kernel.org with ESMTP id S267218AbUBMWlm (ORCPT ); Fri, 13 Feb 2004 17:41:42 -0500 Date: Fri, 13 Feb 2004 23:39:49 +0100 From: Willy Tarreau To: Timothy Miller Cc: Linux Kernel Mailing List Subject: Re: File system performance, hardware performance, ext3, 3ware RAID1, etc. Message-ID: <20040213223949.GA13937@alpha.home.local> References: <402C0D0F.6090203@techsource.com> <20040213055350.GG29363@alpha.home.local> <402D235F.7030401@techsource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <402D235F.7030401@techsource.com> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 13, 2004 at 02:19:59PM -0500, Timothy Miller wrote: > Assuming that the "buffered" speeds are being buffered by the OS, we'll > ignore those. I am therefore observing that the writes to a single > drive are 3 to 4 times faster than they are through the RAID controller, > even with the 3ware write cache ON. > > Does that make any sense? Well, it reminds me a disk I had problems with several years ago. It had a few defects in the FAT area, which were relocated at the end. Performance was terrible since the head had to move constantly. It took ages to install Win31 on it, so it finally was returned to the vendor. But in your case it seems a little bit different since you experience slow writes anywhere on the medium. Would it be possible that your controller does something like read-modify-write because of too big chunk size ? Regards, Willy