From owner-freebsd-fs@FreeBSD.ORG Mon Sep 10 22:07:52 2007 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BBC4F16A418 for ; Mon, 10 Sep 2007 22:07:52 +0000 (UTC) (envelope-from cb@severious.net) Received: from ion.gank.org (ion.gank.org [69.55.238.164]) by mx1.freebsd.org (Postfix) with ESMTP id AB77013C442 for ; Mon, 10 Sep 2007 22:07:52 +0000 (UTC) (envelope-from cb@severious.net) Received: by ion.gank.org (Postfix, from userid 1001) id 6974411A7B; Mon, 10 Sep 2007 17:07:52 -0500 (CDT) Date: Mon, 10 Sep 2007 17:07:51 -0500 From: Craig Boston To: Peter Schuller Message-ID: <20070910220751.GC10142@nowhere> Mail-Followup-To: Craig Boston , Peter Schuller , freebsd-fs@freebsd.org References: <46E4225F.1020806@gmx.net> <46E42D14.5060605@FreeBSD.org> <20070909200933.GA98161@hyperion.scode.org> <46E45E54.6040207@FreeBSD.org> <20070909221142.GA6435@hyperion.scode.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070909221142.GA6435@hyperion.scode.org> User-Agent: Mutt/1.4.2.3i Cc: freebsd-fs@freebsd.org Subject: Re: UFS not handling errors correctly X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Sep 2007 22:07:52 -0000 On Mon, Sep 10, 2007 at 12:11:42AM +0200, Peter Schuller wrote: > Kris Kenneway said: > > Unfortunately there are many ways in which this can fail, mostly involving > > external factors violating the assumptions upon which soft updates relies. > > For example, the data written on disk may not correspond to the data > > dispatched by soft updates, due to things like write caching in the > > hardware, write reordering, data corruption, unpredictable disk behaviour > > during power loss, hardware failure, etc. > > I am aware of this too (and paranoid about it). Although it's still branded experimental for now, you may want to look at ZFS after the 7.0 release. There's a whole host of things to consider (different performance characteristics, possible patent problems, etc), but it's one of the most paranoid filesystems I've seen. It doesn't really trust that the disk actually works correctly and goes to great lengths to recover from read failure or random data corruption. It still sometimes panics on write failure, but that may be considered a feature. Craig