From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750818AbWGDM4h (ORCPT ); Tue, 4 Jul 2006 08:56:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750965AbWGDM4h (ORCPT ); Tue, 4 Jul 2006 08:56:37 -0400 Received: from embla.aitel.hist.no ([158.38.50.22]:51861 "HELO embla.aitel.hist.no") by vger.kernel.org with SMTP id S1750818AbWGDM4h (ORCPT ); Tue, 4 Jul 2006 08:56:37 -0400 Date: Tue, 4 Jul 2006 14:52:27 +0200 To: Valdis.Kletnieks@vt.edu Cc: Bill Davidsen , linux-kernel@vger.kernel.org Subject: Re: ext4 features Message-ID: <20060704125227.GC11458@aitel.hist.no> References: <20060701163301.GB24570@cip.informatik.uni-erlangen.de> <20060701170729.GB8763@irc.pl> <20060701174716.GC24570@cip.informatik.uni-erlangen.de> <20060701181702.GC8763@irc.pl> <20060703202219.GA9707@aitel.hist.no> <44A98D5A.5030508@tmr.com> <200607032150.k63LoM4H027543@turing-police.cc.vt.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200607032150.k63LoM4H027543@turing-police.cc.vt.edu> User-Agent: Mutt/1.5.11+cvs20060403 From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 03, 2006 at 05:50:22PM -0400, Valdis.Kletnieks@vt.edu wrote: > On Mon, 03 Jul 2006 17:34:18 EDT, Bill Davidsen said: > > I think he is talking about another problem. RAID addresses detectable > > failures at the hardware level. I believe that he wants validation after > > the data is returned (without error) from the device. While in most > > cases if what you wrote and what you read don't match it's memory, > > improving the chances of catching the error is useful, given that > > non-server often lacks ECC on memory, or people buy cheaper non-parity > > memory. > > There's other issues as well. Why do people run 'tripwire' on boxes that > have RAID on them? To notice hacking. RAID protects against hardware failure, it does _not_ protect against any change that comes through the normal filesystem channels. RAID doesn't help the slightest against viruses and hackers. RAID is _not_ a backup, when a hacker (or a user error) changes an important file, it is changed in all mirrors of a raid-1 set, and raid-5 checksums are updated so the change becomes valid. But tripwire will notice that a protected file changed. Helge Hafting