Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758942AbYB0U0U (ORCPT ); Wed, 27 Feb 2008 15:26:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757212AbYB0U0H (ORCPT ); Wed, 27 Feb 2008 15:26:07 -0500 Received: from mail.syneticon.net ([213.239.212.131]:35130 "EHLO mail2.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756568AbYB0U0F (ORCPT ); Wed, 27 Feb 2008 15:26:05 -0500 Message-ID: <47C5C74D.3050508@wpkg.org> Date: Wed, 27 Feb 2008 21:25:49 +0100 From: Tomasz Chmielewski User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061110 Mandriva/1.5.0.8-1mdv2007.1 (2007.1) Thunderbird/1.5.0.8 Mnenhy/0.7.4.666 MIME-Version: 1.0 To: Andreas Dilger Cc: Theodore Tso , Andi Kleen , LKML , LKML , linux-raid@vger.kernel.org Subject: Re: very poor ext3 write performance on big filesystems? References: <47B980AC.2080806@wpkg.org> <20080218141640.GC12568@mit.edu> <47C54773.4040402@wpkg.org> <20080227200335.GB9331@webber.adilger.int> In-Reply-To: <20080227200335.GB9331@webber.adilger.int> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1042 Lines: 28 Andreas Dilger schrieb: > I'm CCing the linux-raid mailing list, since I suspect they will be > interested in this result. > > I would suspect that the "journal guided RAID recovery" mechanism > developed by U.Wisconsin may significantly benefit this workload > because the filesystem journal is already recording all of these > block numbers and the MD bitmap mechanism is pure overhead. Also, using anticipatory IO scheduler seems to be the best option for an array with lots of seeks and random reads and writes (quite surprisingly, closely followed by NOOP - both were behaving much better than deadline or CFQ). Here are some numbers I posted to BackupPC mailing list: http://thread.gmane.org/gmane.comp.sysutils.backup.backuppc.general/14009 -- Tomasz Chmielewski http://wpkg.org -- 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/