From owner-freebsd-stable@FreeBSD.ORG Wed Jan 14 04:53:56 2004 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B615B16A4CE for ; Wed, 14 Jan 2004 04:53:56 -0800 (PST) Received: from osku.suutari.iki.fi (osku.syncrontech.com [213.28.98.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id C23AF43D3F for ; Wed, 14 Jan 2004 04:53:52 -0800 (PST) (envelope-from ari@suutari.iki.fi) Received: from coffee.syncrontech.com (coffee.syncrontech.com [62.71.8.37]) by osku.suutari.iki.fi (8.12.8p1/8.12.8) with ESMTP id i0ECrodf024538 for ; Wed, 14 Jan 2004 14:53:51 +0200 (EET) (envelope-from ari@suutari.iki.fi) From: Ari Suutari Organization: At Home To: freebsd-stable@freebsd.org Date: Wed, 14 Jan 2004 14:53:50 +0200 User-Agent: KMail/1.5.4 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200401141453.50150.ari@suutari.iki.fi> Subject: Adaptect raid performance with FreeBSD X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Jan 2004 12:53:56 -0000 Hi, I have been wondering if my disk setup should perform better than it is now doing. I have a dual PIII 500 Mhz with intel server mother board. (a couple of years old). On that, I have DPT (or currently Adaptec) raid controller "DPT PM2654U2", which supports 40 Mhz SCSI bus, giving a theoretical data transfer speed of 80 MB/s. There are two physical disks, which have been mirrored (ie. raid-1). The disks are maxtor atlas 10K4, I think that maxtor tells that they should give sustained transfer rate up to 72MB/s. I have confirmed that SCSI bus is at 80MB/s speed with dptutil. The system is running FreeBSD 4.8. However, when reading raw device with dd like this: dd if=/dev/rda1s1a of=/dev/null bs=1m count=100 100+0 records in 100+0 records out 104857600 bytes transferred in 4.193832 secs (25002814 bytes/sec) So, I get only about 25MB/s. Shouldn't I be getting something like 70 MB/s, or even more since there are two disks that can server read requests ? Maybe there is something I could tune ? The BIOS doesn't have much, there is only setting to enable bus mastering (enabled) and another for pci latency timer values (was 40, I think) Ari S. -- Ari Suutari Lemi, Finland