Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755470AbXFUJAF (ORCPT ); Thu, 21 Jun 2007 05:00:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753484AbXFUI7x (ORCPT ); Thu, 21 Jun 2007 04:59:53 -0400 Received: from s2.ukfsn.org ([217.158.120.143]:44685 "EHLO mail.ukfsn.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752830AbXFUI7w (ORCPT ); Thu, 21 Jun 2007 04:59:52 -0400 Message-ID: <467A3DF8.2080008@dgreaves.com> Date: Thu, 21 Jun 2007 09:59:36 +0100 From: David Greaves User-Agent: Mozilla-Thunderbird 2.0.0.0 (X11/20070601) MIME-Version: 1.0 To: david@lang.hm Cc: David Chinner , Neil Brown , Avi Kivity , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: limits on raid References: <18034.479.256870.600360@notabene.brown> <18034.3676.477575.490448@notabene.brown> <467273AB.9010202@argo.co.il> <18035.3009.568832.785308@notabene.brown> <20070618045759.GD85884050@sgi.com> <18041.59628.370832.633244@notabene.brown> <20070621063936.GT85884050@sgi.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 918 Lines: 22 david@lang.hm wrote: > On Thu, 21 Jun 2007, David Chinner wrote: > one of the 'killer features' of zfs is that it does checksums of every > file on disk. so many people don't consider the disk infallable. > > several other filesystems also do checksums > > both bitkeeper and git do checksums of files to detect disk corruption How different is that to raid1/5/6 being set to a 'paranoid' "read-verify" mode (as per Dan's recent email) where a read reads from _all_ spindles and verifies (and with R6 maybe corrects) the stripe before returning it? Doesn't solve DaveC's issue about the fs doing redundancy but isn't that essentially just fs level mirroring? David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/