From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karthik Sarangan Subject: SCSI disk speed inconsistency Date: Mon, 03 Oct 2005 14:36:51 +0530 Message-ID: <4340F4AB.3070107@cdac.in> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.cdacindia.com ([203.199.132.35]:37615 "HELO mailx.cdac.ernet.in") by vger.kernel.org with SMTP id S932195AbVJCJNk (ORCPT ); Mon, 3 Oct 2005 05:13:40 -0400 Received: from mailhub.cdac.in ([196.1.109.254]) by mailx.cdac.ernet.in (SAVSMTP 3.1.0.29) with SMTP id M2005100314432103550 for ; Mon, 03 Oct 2005 14:43:22 +0530 Received: from mailhub.cdac.in (mailhub [196.1.109.254]) by mailhub.cdac.in (8.13.4/8.13.4) with ESMTP id j939Cvr3031585 for ; Mon, 3 Oct 2005 14:42:57 +0530 Received: from [192.168.5.68] (karthiks.htdg.cdac.ernet.in [192.168.5.68]) by mailhub.cdac.in (8.13.4/8.13.4) with ESMTP id j939Cu0J031579 for ; Mon, 3 Oct 2005 14:42:57 +0530 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Linux SCSI Mailing List I get a read speed of 69MBps from my SCSI disk and a write speed of 49MBps from the same. An IOMeter benchmark on the net says that 68MBps is the sustained speed for a write. Could someone tell me how to increase my IO speed? I have a Linux Kernel 2.6 in a RedHat Enterprise Linux WS 4 and I used the foll. Read : sg_dd if=/dev/sdb of=/dev/null bs=262144 count=1024 dio=1 Write: sg_dd if=/dev/zero of=/dev/sdb bs=262144 count=1024 dio=1