From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932458AbWGaVWL (ORCPT ); Mon, 31 Jul 2006 17:22:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932529AbWGaVWL (ORCPT ); Mon, 31 Jul 2006 17:22:11 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:7853 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S932458AbWGaVWK (ORCPT ); Mon, 31 Jul 2006 17:22:10 -0400 Subject: Re: the " 'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion From: Alan Cox To: Gregory Maxwell Cc: Clay Barnes , Rudy Zijlstra , Adrian Ulrich , vonbrand@inf.utfsm.cl, ipso@snappymail.ca, reiser@namesys.com, lkml@lpbproductions.com, jeff@garzik.org, tytso@mit.edu, linux-kernel@vger.kernel.org, reiserfs-list@namesys.com In-Reply-To: References: <1153760245.5735.47.camel@ipso.snappymail.ca> <20060731144736.GA1389@merlin.emma.line.org> <20060731175958.1626513b.reiser4@blinkenlights.ch> <20060731162224.GJ31121@lug-owl.de> <20060731173239.GO31121@lug-owl.de> <20060731181120.GA9667@merlin.emma.line.org> <20060731184314.GQ31121@lug-owl.de> <20060731191712.GE17206@HAL_5000D.tc.ph.cox.net> <1154374923.7230.99.camel@localhost.localdomain> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Mon, 31 Jul 2006 22:40:26 +0100 Message-Id: <1154382026.7230.110.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ar Llu, 2006-07-31 am 17:00 -0400, ysgrifennodd Gregory Maxwell: > On 7/31/06, Alan Cox wrote: > > Its well accepted that reiserfs3 has some robustness problems in the > > face of physical media errors. The structure of the file system and the > > tree basis make it very hard to avoid such problems. XFS appears to have > > managed to achieve both robustness and better data structures. > > > > How reiser4 compares I've no idea. > > Citation? Two sources, the cases I've looked at myself when IDE maintainer and also comments Hans made when we met at UKUUG a few years ago. Generally speaking on an IDE failure that lost chunks of disk the ext2/ext3 users got most of their data back. The reiserfs ones sometimes got it back and sometimes got catastrophic failure. The ext3 fsck is extremely effective in the face of serious errors. Some of that is clever code that knows about things like rewriting inode blocks to force reallocation of failed metadata by the drive but the majority of it is simply because you *know* where inode X is on the disk rather than having to deal with data structures and walk them. That's a tradeoff with the reiser performance with small files and until recently the reiser large directory performance. Which is right is another question altogether. Its also something I think XFS demonstrates can be done better so doesn't invalidate the theory behind reiserfs just the rev 3 implementation. > Are you sure that you aren't commenting on cases where Reiser3 alerts > the user to a critical data condition (via a panic) which leads to a > trouble report while ext3 ignores the problem which suppresses the > trouble report from the user? man mount Ext3 is configurable, and has been for years via the errors= option. Alan