From owner-freebsd-fs@FreeBSD.ORG Thu Mar 10 11:38:48 2005 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6B82D16A4CE; Thu, 10 Mar 2005 11:38:48 +0000 (GMT) Received: from postfix3-2.free.fr (postfix3-2.free.fr [213.228.0.169]) by mx1.FreeBSD.org (Postfix) with ESMTP id E22AD43D5F; Thu, 10 Mar 2005 11:38:47 +0000 (GMT) (envelope-from tataz@tataz.chchile.org) Received: from tatooine.tataz.chchile.org (vol75-8-82-233-239-98.fbx.proxad.net [82.233.239.98]) by postfix3-2.free.fr (Postfix) with ESMTP id D4CC0C165; Thu, 10 Mar 2005 12:38:46 +0100 (CET) Received: by tatooine.tataz.chchile.org (Postfix, from userid 1000) id 79A85407C; Thu, 10 Mar 2005 12:38:43 +0100 (CET) Date: Thu, 10 Mar 2005 12:38:43 +0100 From: Jeremie Le Hen To: David Schultz Message-ID: <20050310113843.GJ34822@obiwan.tataz.chchile.org> References: <200503091838.06322.mi+mx@aldan.algebra.com> <20050310023518.GA11712@VARK.MIT.EDU> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050310023518.GA11712@VARK.MIT.EDU> User-Agent: Mutt/1.5.8i cc: freebsd-fs@FreeBSD.ORG cc: Mikhail Teterin cc: hackers@FreeBSD.ORG Subject: Re: the current status of nullfs, unionfs X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Mar 2005 11:38:48 -0000 Hi David, > Nullfs works better than unionfs. Unionfs worked well in 4.X. > Despite numerous minor bugs such as being unable to cope with > FIFOs, several people have reported using it quite successfully on > production systems. However, unionfs no longer works quite as > well in 5.X or -CURRENT. There are several reasons for this: > > 1. Nobody seems to have both the time and interest to maintain it. > > 2. Developers can't be expected to prevent regressions in > something that's unsupported. > > 3. There are a couple of people who always respond to questions > about unionfs with comments along the lines of: > ``It's broken, so we won't help you. Go away and don't tell > us if you find any bugs.'' > > There's some pretty low-hanging fruit in terms of nits to fix. > See the PR database if you're interested in helping, and don't let > anyone scare you away. ;-) > > > What about the `union' option to regular mounts? Is that safe to use? > > Last I checked, it was very broken, but I'm not sure. A little time ago, phk@ asked for people to submit regression tests for virtual filesystem like this [1]. AFAIK, nobody submitted even one test so far. This could be a good starting point to have unionfs work correctly again. However, I think FreeBSD VFS gurus should first spread some ideas and clues about tests to do. I guess indeed there are very tricky ones that most common mortals wouldn't even suspect. Regards, [1] http://lists.freebsd.org/pipermail/freebsd-current/2005-January/045743.html -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >