From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751283AbWGDLTS (ORCPT ); Tue, 4 Jul 2006 07:19:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751284AbWGDLTS (ORCPT ); Tue, 4 Jul 2006 07:19:18 -0400 Received: from khc.piap.pl ([195.187.100.11]:34528 "EHLO khc.piap.pl") by vger.kernel.org with ESMTP id S1751283AbWGDLTS (ORCPT ); Tue, 4 Jul 2006 07:19:18 -0400 To: Neil Brown Cc: Alan Cox , Arjan van de Ven , Tomasz Torcz , Helge Hafting , Thomas Glanzmann , "Theodore Ts'o" , LKML Subject: Re: ext4 features (checksums) 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> <1151960503.3108.55.camel@laptopd505.fenrus.org> <1151964720.16528.22.camel@localhost.localdomain> <17577.43190.724583.146845@cse.unsw.edu.au> From: Krzysztof Halasa Date: Tue, 04 Jul 2006 13:19:11 +0200 In-Reply-To: <17577.43190.724583.146845@cse.unsw.edu.au> (Neil Brown's message of "Tue, 4 Jul 2006 09:31:02 +1000") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Neil Brown writes: > With checksums - the filesystem is in a better position to: > - be selective about what is checksummed - no point checksumming > blocks that aren't part of any file. Some blocks (highlevel > metadata) might always be checksummed, while other blocks > (regular data) might not if a 'fast' option was chosen. The same applies to RAID - for example, why "synchronise" unused area? While fs vs. RAID provides a good layering scheme and is easier, integrating them into one entity (as with ZFS) would certainly be more efficient (and probably harder to maintain). -- Krzysztof Halasa