Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 13 Nov 2001 09:29:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 13 Nov 2001 09:29:35 -0500 Received: from mustard.heime.net ([194.234.65.222]:53209 "EHLO mustard.heime.net") by vger.kernel.org with ESMTP id ; Tue, 13 Nov 2001 09:29:16 -0500 Date: Tue, 13 Nov 2001 15:29:13 +0100 (CET) From: Roy Sigurd Karlsbakk To: cc: Subject: Tuning Linux for high-speed disk subsystems Message-ID: 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 Hi all After some testing at Compaq's lab in Oslo, I've come to the conclusion that Linux cannot scale higher than about 30-40MB/sec in or out of a hardware or software RAID-0 set with several stripe/chunk sizes tried out. The set is based on 5 18GB 10k disks running SCSI-3 (160MBps) alone on a 32bit/33MHz PCI bus. After speking to the storage guys here, I was told the problem generally was that the OS should send the data requests at 256kB block sizes, as the drives (10k) could handle 100 I/O operations per second, and thereby could give a total of (256*100)kB/sec per spindle. When using smaller block sizes, the speed would decrease in a linear fasion. Does anyone know this stuff good enough to help me how to tune the system? PS: The CPUs were almost idle during the test. Tested file system was ext2. Regards roy -- Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA Computers are like air conditioners. They stop working when you open Windows. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/