From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario Giammarco Subject: Re: Best driver for qlogic 2200 fc? Date: Tue, 18 Nov 2003 20:19:52 +0100 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1069183192.4927.3.camel@cala> References: <200311171711.36441.mgiammarco@virgilio.it> <1069085218.14602.63.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from vsmtp4.tin.it ([212.216.176.224]:41137 "EHLO vsmtp4.tin.it") by vger.kernel.org with ESMTP id S263770AbTKRTUB (ORCPT ); Tue, 18 Nov 2003 14:20:01 -0500 In-Reply-To: <1069085218.14602.63.camel@localhost.localdomain> List-Id: linux-scsi@vger.kernel.org To: Craig Tierney , linux-scsi@vger.kernel.org Il lun, 2003-11-17 alle 17:06, Craig Tierney ha scritto: > > Unfortunately it gives me slow performance (sequential read of 30mb/sec on a > > seagate 318452fc that can do 60mb/sec sequential read). > > > > What is your write performance? Have you tried > to tune /proc/sys/vm/{min,max}-readahead? I have tuned readahead and not it goes 50 mb. I am shocked, why I need to tune it? Usually I do an hdparm -t -T to see if hard disk is good (and eventually hdparm again to tune ide interface) Without tuning I can reach sequential read of more than 60 mb using raid0. I do not understand why the OS cannot use the full speed of this FC drive. OTOH side I discovered that (in a raid1 array ) the two seagate write speed is very low: 10mb/s, why?