From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mirko Benz Subject: SATA on mptsas performance Date: Mon, 13 Feb 2006 15:01:53 +0100 Message-ID: <43F09151.3010000@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from 162.237.ddkom.net ([212.80.237.162]:5524 "EHLO cheetah.dd.xiranet.com") by vger.kernel.org with ESMTP id S1750938AbWBMOCQ (ORCPT ); Mon, 13 Feb 2006 09:02:16 -0500 Received: from [192.168.0.242] (dhcp242.dd.xiranet.com [192.168.0.242]) (authenticated bits=0) by cheetah.dd.xiranet.com (8.13.4/8.13.4/Debian-1) with ESMTP id k1DE1wgQ030906 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Mon, 13 Feb 2006 15:02:02 +0100 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org Hello, We are testing the following setup: - LSI SAS3442X controller - Promise J300S SAS JBOD connected via the external port of the SAS controller - 10 SATA disks (Seagate) in the JBOD - Linux kernel 2.6.16RC2 on a INTEL Dual Xeon Server, 2.8 Ghz, 64 bit mode LSI SAS driver provided by the kernel finds the JBOD and the disks. Single disk performance is like attaching via a SATA controller from the chipset. Testing with multiple parallel drive accesses gives very poor results and high system utilisation. Tests performed with parallel invocations of dd with bs=32k. Values in MB/s. # of disks READ AVG WRITE AVG 1 60 60,0 58 58,0 5 310 62,0 288 57,6 6 344 57,3 336 56,0 7 259 37,0 375 53,6 8 226 28,3 391 48,9 9 245 27,2 402 44,7 10 265 26,5 405 40,5 Up to 5 drives it looks as it should. Then the performance goes significantly down for READ operations. The card is plugged in a 100 MHz PCI-X slot. No other activity on the system. Any hint? Thanks, Mirko