From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263492AbTDCTJp (for ); Thu, 3 Apr 2003 14:09:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263489AbTDCTJH (for ); Thu, 3 Apr 2003 14:09:07 -0500 Received: from node181b.a2000.nl ([62.108.24.27]:16778 "EHLO ddx.a2000.nu") by vger.kernel.org with ESMTP id S263485AbTDCTIm (for ); Thu, 3 Apr 2003 14:08:42 -0500 Date: Thu, 3 Apr 2003 21:20:29 +0200 (CEST) From: Stephan van Hienen To: "Peter L. Ashford" cc: Jonathan Vardy , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: RAID 5 performance problems In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 3 Apr 2003, Peter L. Ashford wrote: > 1. Disk controllers (get off the motherboard IDE, dump the FastTrak, use > Master only) fasttrak is nothing more than an ultra version with an special bios if you don't use this raid bios, there is no difference (for linux) > 2. I/O bandwidth (multiple PCI buses) sure this helps, but he is not even getting near the pci bus limitations... > 3. Memory bandwidth (switch to something like a P4) my old dual p2-500 had didn't have this problem (i'm 'the friend' look at the last benchmark (5*80gb raid5) > 4. Disks (this is where your friend's dual Xeon system is) eh, disks are not really his problem (he is getting 30mb/sec with hdparm for each disk, but getting same result for his /dev/md0) > > Your network probably belongs in this list somewhere, but you didn't he didn't test any network performance yet, this is just plain disk benchmarking... > 26MB/S (there should be almost no difference for the BB drives). My > suggestion would be to remove the FastTrak, and get two Ultra-100s and an > Ultra-133 (or one Ultra-100 and two Ultra-133s). Use one disk per channel there is absolutly no performance difference between an fasttrak-100 and an ultra-100 here benchmark from my system with an fasttrak-tx4 (same card jonathan has) with WD1800BB : /dev/hde: Timing buffer-cache reads: 128 MB in 0.28 seconds =457.14 MB/sec Timing buffered disk reads: 64 MB in 1.37 seconds = 46.72 MB/sec WD1800BB on onboard ultra100 controller : /dev/hdo: Timing buffer-cache reads: 128 MB in 0.28 seconds =457.14 MB/sec Timing buffered disk reads: 64 MB in 1.58 seconds = 40.51 MB/sec WD1800BB on onboard ultra33 controller : /dev/hda: Timing buffer-cache reads: 128 MB in 0.28 seconds =457.14 MB/sec Timing buffered disk reads: 64 MB in 2.55 seconds = 25.10 MB/sec > > His raid: > > > > 99MB/S block write, 178MB/S block read > > This MUST have had a better disk controller system AND multiple PCI buses. > The limit of one PCI bus (32-bit/33MHz, as used by the Promise > controllers) is 133MB/S, and they are exceeding that. correct, 3 pci busses but my old system was only 1 pci bus (same mainbord Jonathan is using) but was getting way higher performance (his raid is getting lower performance than an single disk) with only 150mhz more per cpu