Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759674AbZDOMqT (ORCPT ); Wed, 15 Apr 2009 08:46:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759523AbZDOMqE (ORCPT ); Wed, 15 Apr 2009 08:46:04 -0400 Received: from brick.kernel.dk ([93.163.65.50]:46404 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758378AbZDOMqC (ORCPT ); Wed, 15 Apr 2009 08:46:02 -0400 Date: Wed, 15 Apr 2009 14:46:01 +0200 From: Jens Axboe To: Chris Mason Cc: Andi Kleen , Michael Tokarev , Mark Lord , Anton Ertl , linux-kernel@vger.kernel.org, agk@redhat.com Subject: Re: Out-of-order writing by disk drives Message-ID: <20090415124601.GM5178@kernel.dk> References: <87r5zv72cl.fsf@basil.nowhere.org> <20090414172406.GX14687@one.firstfloor.org> <49E4CA75.902@rtr.ca> <20090414175433.GY14687@one.firstfloor.org> <49E4D16C.7030809@msgid.tls.msk.ru> <20090414185058.GZ14687@one.firstfloor.org> <1239737226.28321.22.camel@think.oraclecorp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1239737226.28321.22.camel@think.oraclecorp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1193 Lines: 31 On Tue, Apr 14 2009, Chris Mason wrote: > On Tue, 2009-04-14 at 20:50 +0200, Andi Kleen wrote: > > On Tue, Apr 14, 2009 at 10:09:48PM +0400, Michael Tokarev wrote: > > > Andi Kleen wrote: > > > [] > > > >Where I see it as a problem is with virtualization; LVM seems to be the > > > >most sane way to manage file systems for lots of VMs and you likely > > > >want barriers there too. > > > > > > Virtualisation is the best fit for partitionable raid1 arrays. > > > It is, in fact, what we have here -- I tested LVM but rejected > > > it because of this very issue - it does not support barriers. > > > > It does now as of 2.6.29, as long as you only have a single > > underlying device and use dm linear. > > Eric Sandeen noticed this is actually still broken: > > http://lkml.org/lkml/2009/3/23/360 Alasdair promised to push the remaining barrier bits for 2.6.30, so hopefully it should all be in working order Real Soon Now. -- Jens Axboe -- 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/