From: Dave Johnson Subject: Re: [ext3] kjournald writing after each read despite noatime,commit=nnn Date: Thu, 1 Jan 2009 14:35:20 -0500 Message-ID: <18781.6904.837987.584032@wellington.i202.centerclick.org> References: <18779.58377.160214.225792@wellington.i202.centerclick.org> <495CCCDF.3030606@samwel.tk> <18780.62500.100687.402706@wellington.i202.centerclick.org> <495D12A8.9030703@samwel.tk> <18781.5890.617086.393467@wellington.i202.centerclick.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org To: Bart Samwel Return-path: Received: from lexington.centerclick.org ([66.114.92.10]:34510 "EHLO lexington.centerclick.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757074AbZAATfZ (ORCPT ); Thu, 1 Jan 2009 14:35:25 -0500 In-Reply-To: <18781.5890.617086.393467@wellington.i202.centerclick.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Dave Johnson writes: > Bart Samwel writes: > > This looks like it's a generic property of syncing an ext3 file system. > > Try turning off laptop_mode and then running "sync". You will probably > > see the same behaviour. > > yep, every sync() causes a gratuitous write to disk N seconds later > even when no data has been read or written since the last sync(). Woops, correction, every sync() call causes a single gratuitous write, no delay. $ for n in 1 2 3 4 5; do sync; done Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2682 on hda1 Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2684 on hda1 Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2686 on hda1 Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2688 on hda1 Jan 1 14:32:54 gw kernel: kjournald(760): WRITE block 2690 on hda1 -- Dave