From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Thu, 29 Mar 2007 07:56:38 -0700 (PDT) Received: from mail.lichtvoll.de (mondschein.lichtvoll.de [194.150.191.11]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l2TEuQ6p016012 for ; Thu, 29 Mar 2007 07:56:31 -0700 Received: from localhost (dslb-084-057-114-201.pools.arcor-ip.net [84.57.114.201]) by mail.lichtvoll.de (Postfix) with ESMTP id BD4865AD36 for ; Thu, 29 Mar 2007 16:56:23 +0200 (CEST) From: Martin Steigerwald Subject: Re: XFS and write barriers. Date: Thu, 29 Mar 2007 16:56:21 +0200 References: <17923.11463.459927.628762@notabene.brown> <17927.19372.553410.527506@notabene.brown> <20070326090456.GO32597093@melbourne.sgi.com> In-Reply-To: <20070326090456.GO32597093@melbourne.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Message-Id: <200703291656.22084.Martin@lichtvoll.de> Content-Transfer-Encoding: 8bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: linux-xfs@oss.sgi.com Am Montag 26 März 2007 schrieb David Chinner: > > Is there some mount flag to say "cope without barriers" or "require > > barriers" ?? > > XFs has "-o nobarrier" to say don't use barriers, and this is > *not* the default. If barriers don't work, we drop back to "-o > nobarrier" after leaving a loud warning inthe log.... Hello David! Just a thought, maybe it shouldn't do that automatically, but require the sysadmin to explicitely state "-o nobarrier" in that case. Safest default behavior IMHO would be either not to mount at all without "-o nobarrier" if the device has no barrier support or disable the write cache of that device. The latter can be considered a layering violation in itself. BTW XFS copes really well here with commodity hardware such as my ThinkPads with 2.5 inch notebook harddisks *since* 2.6.17.7. But right now I wondered about barrier support on USB connected devices? I have to check whether XFS does barriers on those. Does the usb mass storage driver support barriers? Regards, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7