From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx.in-addr.de (gate.in-addr.de [212.8.193.158]) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTP id 254F410622A9 for ; Tue, 22 Sep 2009 08:21:10 +0200 (CEST) Date: Tue, 22 Sep 2009 08:20:34 +0200 From: Lars Marowsky-Bree To: FUJITA Tomonori , lars.ellenberg@linbit.com Message-ID: <20090922062034.GE22732@suse.de> References: <20090921144308.GG8072@barkeeper1-xen.linbit> <20090921165252.04e335b1@infradead.org> <20090921165321.GJ8072@barkeeper1-xen.linbit> <20090922072617U.fujita.tomonori@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20090922072617U.fujita.tomonori@lab.ntt.co.jp> Cc: bart.vanassche@gmail.com, kyle@moffetthome.net, sam@ravnborg.org, neilb@suse.de, knikanth@suse.de, gregkh@suse.de, linux-kernel@vger.kernel.org, philipp.reisner@linbit.com, hch@infradead.org, Mauelshagen@redhat.com, James.Bottomley@suse.de, kosaki.motohiro@jp.fujitsu.com, jens.axboe@oracle.com, davej@redhat.com, akpm@linux-foundation.org, drbd-dev@lists.linbit.com, torvalds@linux-foundation.org, arjan@infradead.org Subject: Re: [Drbd-dev] [GIT PULL] DRBD for 2.6.32 List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2009-09-22T07:27:21, FUJITA Tomonori wrote: > > If it happens, once that happens, that _will_ be an ABI break. > > You misunderstand the raid unification. > > We will not unify the kernel<->userspace configuration interface > because we can't break the kernel<->userspace ABI. I disagree here. Who says we can't over time, and with due notice? For sure, the new ABI needs to co-exist with the old ones for a while, until it is proven and fully complete, but then, why can't the old one be marked as depreciated and phased out over 1-2 years time? Users won't notice. Modern distros will switch, and in cases of legacy distros ("enterprise"), the vendors will backport appropriately. This happens. There's precedence with the network filtering rules etc. > We plan to unify the multiple device frameworks, but the unified > framework must support the all existing ABIs. > > So adding another 'drbd' ABI hurts us. Even that doesn't really apply, I think. If the new framework is powerful enough and a super-set of everything that came before, the shim layer will be somewhat annoying, but harmless code. Regards, Lars -- Architect Storage/HA, OPS Engineering, Novell, Inc. SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg) "Experience is the name everyone gives to their mistakes." -- Oscar Wilde