Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753222AbZISX4N (ORCPT ); Sat, 19 Sep 2009 19:56:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752205AbZISX4M (ORCPT ); Sat, 19 Sep 2009 19:56:12 -0400 Received: from mail-vw0-f195.google.com ([209.85.212.195]:48139 "EHLO mail-vw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088AbZISX4M (ORCPT ); Sat, 19 Sep 2009 19:56:12 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; b=x7bxgtA5ht8MeA5vjTViOrh1+dCmnJMNKUUwBDI9FXRawH7NVgBZaNjjFBygpxDT3/ KqBWC56p+8dfT54b5zDh2NlamKxkSI2rH1Sh7nHwkuZo2tael9n6PGJAAJ4gK37ObLdD sXok+AxET/I00i2CVSseNGeo6WzjgJUcut84I= MIME-Version: 1.0 In-Reply-To: <20090919220232.GB31849@suse.de> References: <20090917161108.GA3361@infradead.org> <19122.65335.126937.476968@notabene.brown> <20090918200803.GM23126@kernel.dk> <20090919141334N.fujita.tomonori@lab.ntt.co.jp> <20090919220232.GB31849@suse.de> Date: Sat, 19 Sep 2009 16:56:15 -0700 X-Google-Sender-Auth: c76a36c04121a13b Message-ID: Subject: Re: [GIT PULL] DRBD for 2.6.32 From: Dan Williams To: Lars Marowsky-Bree Cc: FUJITA Tomonori , jens.axboe@oracle.com, neilb@suse.de, hch@infradead.org, James.Bottomley@suse.de, lars.ellenberg@linbit.com, linux-kernel@vger.kernel.org, drbd-dev@lists.linbit.com, akpm@linux-foundation.org, bart.vanassche@gmail.com, davej@redhat.com, gregkh@suse.de, kosaki.motohiro@jp.fujitsu.com, kyle@moffetthome.net, torvalds@linux-foundation.org, nab@linux-iscsi.org, knikanth@suse.de, philipp.reisner@linbit.com, sam@ravnborg.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1772 Lines: 42 On Sat, Sep 19, 2009 at 3:02 PM, Lars Marowsky-Bree wrote: > On 2009-09-19T14:14:30, FUJITA Tomonori wrote: > >> I guess that Christoph is worry about adding another user interface >> for kinda device management; once we merge this, we can't fix it (for >> the raid unification). > > Why can't it be fixed? > > Either > > a) there's going to be a transition period during which the "old" > interface is supported but depreciated and scheduled to be removed (all > driving the new unified same back-end), > > or b) there's going to be a new kernel which requires new user-space > tools sharp. > > In either case, dm/md are affected by this, so a third interface doesn't > really make much difference. The refactoring needs to happen in the > back-end anyway, and that actually becomes easier when all concurrent > implementations are present and can be reworked at the same time. It's actually four "raid" implementations in the kernel if you count the multiple-disk functionality of btrfs. The precedent is already set for merging new multiple-disk management interfaces. Neil has come the closest to actually trying to start (i.e. code) the unification effort [1] and that was for the relatively straightforward case of mapping the dm-raid5 backend to md-raid5... no uptake to date. There are no strictly equivalent drbd-backends in the kernel presently, so leaving this out of tree is a net-loss for mainline. -- Dan [1]: http://marc.info/?l=dm-devel&m=124567352518676&w=2 -- 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/