Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754103Ab0LVQcf (ORCPT ); Wed, 22 Dec 2010 11:32:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:28123 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753478Ab0LVQcd (ORCPT ); Wed, 22 Dec 2010 11:32:33 -0500 From: Jeff Moyer To: Rogier Wolff Cc: Greg Freemyer , Bruno =?utf-8?Q?Pr=C3=A9mont?= , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: Re: Slow disks. References: <20101220141553.GA6088@bitwizard.nl> <20101220190630.66084e1d@neptune.home> <20101222104306.GB30941@bitwizard.nl> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Wed, 22 Dec 2010 11:27:20 -0500 In-Reply-To: <20101222104306.GB30941@bitwizard.nl> (Rogier Wolff's message of "Wed, 22 Dec 2010 11:43:06 +0100") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1688 Lines: 46 Rogier Wolff writes: > Unquoted text below is from either me or from my friend. > > > Someone suggested we try an older kernel as if kernel 2.6.32 would not > have this problem. We do NOT think it suddenly started with a certain > kernel version. I was just hoping to have you kernel-guys help with > prodding the kernel into revealing which component was screwing things > up.... [...] > ata3.00: ATA-8: WDC WD10EARS-00Y5B1, 80.00A80, max UDMA/133 This is an "Advanced format" drive, which, in this case, means it internally has a 4KB sector size and exports a 512byte logical sector size. If your partitions are misaligned, this can cause performance problems. > MDstat: > > Personalities : [raid1] [raid6] [raid5] [raid4] > md125 : active raid5 sdd3[5](S) sdb3[4] sda3[0] sdc3[3] > 3903488 blocks super 1.1 level 5, 512k chunk, algorithm 2 [3/3] [UUU] > > md126 : active raid5 sda4[0] sdd4[3] sdc4[5](S) sdb4[4] > 1910063104 blocks super 1.1 level 5, 512k chunk, algorithm 2 > [3/3] [UUU] > > md1 : active raid5 sda2[0] sdd2[3](S) sdb2[1] sdc2[4] > 39067648 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] > [3/3] [UUU] > > md1 : active raid5 sda2[0] sdd2[3](S) sdb2[1] sdc2[4] > 39067648 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] > [UUU] A 512KB raid5 chunk with 4KB I/Os? That is a recipe for inefficiency. Again, blktrace data would be helpful. Cheers, Jeff -- 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/