From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263619AbTDTPza (ORCPT ); Sun, 20 Apr 2003 11:55:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263620AbTDTPza (ORCPT ); Sun, 20 Apr 2003 11:55:30 -0400 Received: from mail.ithnet.com ([217.64.64.8]:60942 "HELO heather.ithnet.com") by vger.kernel.org with SMTP id S263619AbTDTPz3 (ORCPT ); Sun, 20 Apr 2003 11:55:29 -0400 Date: Sun, 20 Apr 2003 18:07:20 +0200 From: Stephan von Krawczynski To: Jos Hulzink Cc: alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org Subject: Re: Are linux-fs's drive-fault-tolerant by concept? Message-Id: <20030420180720.099b4c34.skraw@ithnet.com> In-Reply-To: <200304192313.53955.josh@stack.nl> References: <20030419180421.0f59e75b.skraw@ithnet.com> <1050766175.3694.4.camel@dhcp22.swansea.linux.org.uk> <200304192313.53955.josh@stack.nl> Organization: ith Kommunikationstechnik GmbH X-Mailer: Sylpheed version 0.8.11 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 19 Apr 2003 23:13:53 +0200 Jos Hulzink wrote: > [...] > Fault tolerance in a filesystem layer means in practical terms that you are > guessing what a filesystem should look like, for the disk doesn't answer that > > question anymore. IMHO you don't want that to be done automagically, for it > might go right sometimes, but also might trash everything on RW filesystems. Let me clarify again: I don't want fancy stuff inside the filesystem that magically knows something about right-or-wrong. The only _very small_ enhancement I would like to see is: driver tells fs there is an error while writing a certain block => fs tries writing the same data onto another block. That's it, no magic, no RAID stuff. Very simple. > Fault tolerance OK, but the fs layer should only detect errors reported by > the lower level drivers and handle them gracefully (which is something that > might need impovement a little for some fs drivers), or else trust the data > it gets. You are completely right, I don't want any more: nice management of an error a low-level driver reports to the fs. Only I would like to see as an fs-answer to this: ok, let's try another part of the media. Currently it just sinks like titanic. Regards, Stephan