From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Greaves Subject: Re: limits on raid Date: Thu, 21 Jun 2007 09:59:36 +0100 Message-ID: <467A3DF8.2080008@dgreaves.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: david@lang.hm Cc: David Chinner , Neil Brown , Avi Kivity , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org List-Id: linux-raid.ids 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