Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758546Ab0HDHg7 (ORCPT ); Wed, 4 Aug 2010 03:36:59 -0400 Received: from isilmar-3.linta.de ([188.40.101.200]:52680 "EHLO linta.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758452Ab0HDHg5 (ORCPT ); Wed, 4 Aug 2010 03:36:57 -0400 Date: Wed, 4 Aug 2010 09:35:46 +0200 From: Dominik Brodowski To: linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org Subject: How to track down abysmal performance ata - raid1 - crypto - vg/lv - xfs Message-ID: <20100804073546.GA7494@comet.dominikbrodowski.net> Mail-Followup-To: Dominik Brodowski , linux-raid@vger.kernel.org, xfs@oss.sgi.com, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1047 Lines: 42 Hey, on a production system I run kernel 2.6.35 and XFS (rw,relatime,nobarrier) on a lvdevice of a vgroup consisting of five dm-crypt devices (cryptsetup -c aes-lrw-benbi -s 384 create) , each of which runs on a md-raid1 device (mdadm --create --level=raid1 --raid-devices=2) on two 750 GB ATA devices. The read performance is abysmal. The ata devices can be ruled out, as hdparm resulted in acceptable performance: > Timing cached reads: 9444 MB in 2.00 seconds = 4733.59 MB/sec > Timing buffered disk reads: 298 MB in 3.02 seconds = 98.73 MB/sec How can I best track down the cause of the performance problem, a) without rebooting too often, and b) without breaking up the setup specified above (production system)? Any ideas? perf(1)? iostat(1)? Thanks & best, Dominik -- 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/