From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750717AbWGFUFL (ORCPT ); Thu, 6 Jul 2006 16:05:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750735AbWGFUFL (ORCPT ); Thu, 6 Jul 2006 16:05:11 -0400 Received: from sccrmhc14.comcast.net ([204.127.200.84]:6904 "EHLO sccrmhc14.comcast.net") by vger.kernel.org with ESMTP id S1750717AbWGFUFK (ORCPT ); Thu, 6 Jul 2006 16:05:10 -0400 Date: Thu, 6 Jul 2006 16:02:30 -0400 From: Tom Vier To: Valerie Henson Cc: LKML , Helge Hafting , Thomas Glanzmann , "Theodore Ts'o" , Andrew Morton Subject: Re: Blatant layering violations (was Re: ext4 features) Message-ID: <20060706200230.GC27533@zero> Reply-To: Tom Vier 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> <20060706003638.GL5231@goober> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060706003638.GL5231@goober> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 05, 2006 at 05:36:39PM -0700, Valerie Henson wrote: > On Mon, Jul 03, 2006 at 10:55:23PM +0200, Tomasz Torcz wrote: > > > > ZFS was already called ,,blatant layering violation''. ;) It buys you some preformance. Someone here already mentioned variable stripe sizes. ZFS doesn't just add a checksum sector after each block (something i've been planning to write an md module for, for a couple years). It writes the checksum at the end of the tree member, inode, dirent, whatever. So there's no read-modify-write when you write < 1 checksum block size. One thing i noticed about zfs that surprised me: it's using indirect blocks, from what i saw. -- Tom Vier DSA Key ID 0x15741ECE