From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263392AbTJOPNm (ORCPT ); Wed, 15 Oct 2003 11:13:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263396AbTJOPNm (ORCPT ); Wed, 15 Oct 2003 11:13:42 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:36501 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S263392AbTJOPNk (ORCPT ); Wed, 15 Oct 2003 11:13:40 -0400 Message-ID: <3F8D6417.8050409@pobox.com> Date: Wed, 15 Oct 2003 11:13:27 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Erik Mouw CC: Josh Litherland , linux-kernel@vger.kernel.org Subject: Re: Transparent compression in the FS References: <1066163449.4286.4.camel@Borogove> <20031015133305.GF24799@bitwizard.nl> In-Reply-To: <20031015133305.GF24799@bitwizard.nl> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Erik Mouw wrote: > On Tue, Oct 14, 2003 at 04:30:50PM -0400, Josh Litherland wrote: > >>Are there any filesystems which implement the transparent compression >>attribute ? (chattr +c) > > > The NTFS driver supports compressed files. Because it doesn't have > proper write support, I don't think it will do anything useful with > chattr +c. > > Nowadays disks are so incredibly cheap, that transparent compression > support is not realy worth it anymore (IMHO). Josh and others should take a look at Plan9's venti file storage method -- archival storage is a series of unordered blocks, all of which are indexed by the sha1 hash of their contents. This magically coalesces all duplicate blocks by its very nature, including the loooooong runs of zeroes that you'll find in many filesystems. I bet savings on "all bytes in this block are zero" are worth a bunch right there. Jeff