From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 08 Jan 2007 09:33:07 -0800 (PST) Received: from service.eng.exegy.net (68-191-203-42.static.stls.mo.charter.com [68.191.203.42]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l08HX1qw028138 for ; Mon, 8 Jan 2007 09:33:03 -0800 Message-ID: <45A27BC7.2020709@exegy.com> Date: Mon, 08 Jan 2007 11:13:43 -0600 From: "Mr. Berkley Shands" MIME-Version: 1.0 Subject: XFS and 2.6.18 -> 2.6.20-rc3 Content-Type: text/plain Content-Disposition: inline Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Eric Sandeen Cc: Dave Lloyd , linux-xfs@oss.sgi.com My testbench is a 4 core Opteron (dual 275's) into two LSI8408E SAS controllers, into 16 Seagate 7200.10 320GB satas. Redhat ES4.4 (Centos 4.4). A slightly newer parted is needed than the contemporary of Moses that is shipped with the O/S. I have a standard burn in script that takes the 4 4-drive raid0's and puts a GPT label on them, aligns the partitions to stripe boundary's. It then proceeds to write 8GB files concurrently onto all 4 raid drives. Under 2.6.18.1 the write speeds start at 265MB/Sec and decrease mostly monotonically down to ~160MB/Sec, indicating that the files start on the outside (fastest tracks) and work in. All 4 raids are within 7-8MB/Sec of each other (usually they are identical in speed). By the time of 2.6.20-rc3, the same testbench shows a 10% across the board decrease in throughput for writes. Reads are unaffected. But now the allocation order for virgin file systems are random, usually starting at the slow 140MB/Sec, then bouncing up to 220MB/Sec, then around and around. No two raids get the same write speeds at the same time. Dave Lloyd (our in-house Idea Guy) looked at the allocation groups... Non-sequential, random... What data would you like to see? The run logs from 2.6.18.1 and 2.6.20-rc3? Want the scripts? The xfs-debug dumps of a few files? Berkley -- //E. F. Berkley Shands, MSc// **Exegy Inc.** 3668 S. Geyer Road, Suite 300 St. Louis, MO 63127 Direct: (314) 450-5348 Cell: (314) 303-2546 Office: (314) 450-5353 Fax: (314) 450-5354 This e-mail and any documents accompanying it may contain legally privileged and/or confidential information belonging to Exegy, Inc. Such information may be protected from disclosure by law. The information is intended for use by only the addressee. If you are not the intended recipient, you are hereby notified that any disclosure or use of the information is strictly prohibited. If you have received this e-mail in error, please immediately contact the sender by e-mail or phone regarding instructions for return or destruction and do not use or disclose the content to others. [[HTML alternate version deleted]]