From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932107AbWGCVB7 (ORCPT ); Mon, 3 Jul 2006 17:01:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932122AbWGCVB7 (ORCPT ); Mon, 3 Jul 2006 17:01:59 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:48835 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932107AbWGCVB6 (ORCPT ); Mon, 3 Jul 2006 17:01:58 -0400 Subject: Re: ext4 features From: Arjan van de Ven To: Tomasz Torcz Cc: Helge Hafting , Thomas Glanzmann , "Theodore Ts'o" , LKML In-Reply-To: <20060703205523.GA17122@irc.pl> 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> <20060703205523.GA17122@irc.pl> Content-Type: text/plain Date: Mon, 03 Jul 2006 23:01:43 +0200 Message-Id: <1151960503.3108.55.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > ZFS was already called ,,blatant layering violation''. ;) > Yes,that what RAID is for. And if we want checksums in filesystem, > that's the best way to utilise them. Hi, checksums have a very different purpose than raid. checksums are great at detecting corruption. And yes, corruption can happen even if you have raid, for many many reasons. Detecting means knowing when to not trust something, when to go for the backup tapes... raid is great for protecting against individual disks or sectors going bad. But raid, especially high performance implementations, do not checksum data or detect corruptions. They're different purpose with almost zero overlap in purpose or even goal...