From: Eric Sandeen Subject: Re: Performance of ext4 Date: Thu, 19 Jun 2008 11:41:17 -0500 Message-ID: <485A8C2D.1090806@redhat.com> References: <18513.345.553912.449710@frecb006361.adech.frec.bull.fr> <20080612131928.GB18229@mit.edu> <20080612180605.GD22481@skywalker> <20080616175408.GF3279@atrey.karlin.mff.cuni.cz> <20080616181353.GA20686@skywalker> <20080619155645.GA8582@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Theodore Tso , Holger Kiehl , "Aneesh Kumar K.V" , Jan Kara , Solofo.Ramangalahy@bull.net, Nick Doko Return-path: Received: from mx1.redhat.com ([66.187.233.31]:42064 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752089AbYFSQwE (ORCPT ); Thu, 19 Jun 2008 12:52:04 -0400 In-Reply-To: <20080619155645.GA8582@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Tso wrote: > On Tue, Jun 17, 2008 at 11:42:36AM +0000, Holger Kiehl wrote: >> Note how the size of file results.24033.helena.dwd.de changes from >> 9230 before the test to 8208 bytes after the test. Also note the >> date both have the same timestamp "2008-06-17 04:35". I have made a >> copy of results.24033.helena.dwd.de before the test and compared it >> with that after the test. The file is just truncated by 1022 bytes >> and there is no garbage. > > So the corruption is always a truncation, correct? > > Did you notice the problem with ext4 w/o the patch queue? I have a > suspicion that the problem may have been introduced by the delayed > allocation code, but I don't have hard evidence. When you rerun your > benchmark (which seems to be the closest thing we have to a > reproduction case), it would be interesting to know if the problem > goes away with -o nodelalloc (again, it would localize where we need > to look). > > Thanks, regards, It might be worth runninga "simple" fsx under your kernel too; last time I tested fsx it was still happy and it exercises fs ops (including truncate) at random... -Eric