Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269334AbUICQfK (ORCPT ); Fri, 3 Sep 2004 12:35:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269366AbUICQfK (ORCPT ); Fri, 3 Sep 2004 12:35:10 -0400 Received: from cpu1185.adsl.bellglobal.com ([207.236.110.166]:63617 "EHLO mail.rtr.ca") by vger.kernel.org with ESMTP id S269334AbUICQfD (ORCPT ); Fri, 3 Sep 2004 12:35:03 -0400 Message-ID: <41389CDA.5060609@rtr.ca> Date: Fri, 03 Sep 2004 12:33:30 -0400 From: Mark Lord User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040803 X-Accept-Language: en, en-us MIME-Version: 1.0 To: "J.A. Magallon" Cc: Lista Linux-Kernel , Jeff Garzik Subject: Re: md RAID over SATA performance References: <1094169937l.17931l.0l@werewolf.able.es> In-Reply-To: <1094169937l.17931l.0l@werewolf.able.es> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 711 Lines: 21 Even with hardware RAID the numbers I see are not often much better than this. Unless O_DIRECT is used (hdparm --direct), in which case they immediately jump to a level that is more limited by the PCI and memory speeds of the system. Eg. 205Mbytes/sec for a 4-drive RAID0 over 64-bit/66Mhz PCI. I guess the page_cache overhead is rather substantial for the simple read-a-sequential-block test. Cheers -- Mark Lord (hdparm keeper & the original "Linux IDE Guy") - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/