From owner-freebsd-current@FreeBSD.ORG Mon Dec 19 21:36:20 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CCBEF16A41F for ; Mon, 19 Dec 2005 21:36:20 +0000 (GMT) (envelope-from matthias.andree@gmx.de) Received: from mail.dt.e-technik.uni-dortmund.de (krusty.dt.E-Technik.uni-dortmund.de [129.217.163.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id A214243D78 for ; Mon, 19 Dec 2005 21:36:18 +0000 (GMT) (envelope-from matthias.andree@gmx.de) Received: from localhost (localhost [127.0.0.1]) by mail.dt.e-technik.uni-dortmund.de (Postfix) with ESMTP id DBF8344129; Mon, 19 Dec 2005 22:36:16 +0100 (CET) Received: from mail.dt.e-technik.uni-dortmund.de ([127.0.0.1]) by localhost (krusty [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 01976-06; Mon, 19 Dec 2005 22:36:15 +0100 (CET) Received: from m2a2.dyndns.org (p5091366B.dip0.t-ipconnect.de [80.145.54.107]) by mail.dt.e-technik.uni-dortmund.de (Postfix) with ESMTP id 122B9440A8; Mon, 19 Dec 2005 22:36:14 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by merlin.emma.line.org (Postfix) with ESMTP id 4308B2018ED; Mon, 19 Dec 2005 22:36:14 +0100 (CET) Received: from m2a2.dyndns.org ([127.0.0.1]) by localhost (m2a2.dyndns.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 06378-02; Mon, 19 Dec 2005 22:36:12 +0100 (CET) Received: by merlin.emma.line.org (Postfix, from userid 500) id D2850201F1F; Mon, 19 Dec 2005 22:36:11 +0100 (CET) From: Matthias Andree To: Justin Smith In-Reply-To: <43A6D190.3020504@drexel.edu> (Justin Smith's message of "Mon, 19 Dec 2005 10:28:16 -0500") References: <43A6D190.3020504@drexel.edu> X-PGP-Key: http://home.pages.de/~mandree/keys/GPGKEY.asc Date: Mon, 19 Dec 2005 22:36:11 +0100 Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: amavisd-new at dt.e-technik.uni-dortmund.de Cc: freebsd-current@freebsd.org Subject: Re: "Native" journaling file systems? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Dec 2005 21:36:21 -0000 Justin Smith writes: > Are there any plans to develop UFS3--- i.e., a UFS2 file system with an > added journal? > > I've used several journaling file systems in Linux and like the Reiser > FS except for one MAJOR drawback: When something goes wrong, reiser-fsck > absolutely sucks at repairing things (Hans Reiser freely admits that but > says it's never needed because nothing ever goes wrong). I have been using reiserfs for a while, but I ultimately dropped it again and reverted to ext3fs because I didn't like the sloppy spelling of the tools to begin with, and the fact that there have always been accumulated inconsistencies in the on-disk file systems on some systems. The recent in-kernel versions have been more stable, and reiserfsck has improved, too, but there are two real showstoppers: 1. the reiserfs team dropped 3.X support and went for reiser4 (I have been told this is reiser4, not reiserfs4, whatever), leaving 3.X issues unresolved 2. reiserfs 3.6 only supports a limited amount of files with the same internal hash code per given unit (I don't recall if unit was directory or file system, probably the former). Some may see this as pathological, but I see it as a problem. 3. data journalling or data ordering, which Linux ext3fs supported, has never made official reiserfs 3.X versions as far as I know, which means NUL blocks showing up in files after crashes. Chris Mason added such support to SUSE kernels. So my bottom line is: investing time into reiserfs 3.X is investing time into a dead product. I know too little about reiser4, but it has been refused entry to the baseline Linux kernel several times on technical grounds, and ultimately the opinions clashed so hard that the reviewer whose opinion was asked threw in the towel. My opinion however is that reiser4 is a new product and will not be ripe before it has been two years in the kernel baseline, and who says that the guys around Hans Reiser haven't moved on to reiser5 by that time? After all, ext3fs supports some dirhash variant ("dir_index") which seems to be pretty unobtrusive, it appears to "just work". I believe the reason why it was separated (in Linux) from the ext2 code is to not introduce instabilities or make the code harder to read. (There's actually another jbd, journalling block device, driver in Linux, that ext3fs uses.) -- Matthias Andree