From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 14 Dec 2001 14:12:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 14 Dec 2001 14:12:04 -0500 Received: from gw.uk.sistina.com ([62.172.100.98]:8711 "EHLO gw.uk.sistina.com") by vger.kernel.org with ESMTP id ; Fri, 14 Dec 2001 14:11:51 -0500 Date: Fri, 14 Dec 2001 19:11:50 +0000 From: Alasdair G Kergon To: linux-kernel@vger.kernel.org Subject: Re: A possible direction for the next LVM driver Message-ID: <20011214191150.C22147@uk.sistina.com> Mail-Followup-To: linux-kernel@vger.kernel.org In-Reply-To: <20010830164547.A807@btconnect.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010830164547.A807@btconnect.com>; from thornber@btconnect.com on Thu, Aug 30, 2001 at 04:45:47PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2001 at 04:45:47PM +0100, Joe Thornber wrote: > I'm working on the next iteration of the LVM driver ...which is now known as the "device-mapper" because it lets you define new block devices that map I/O onto sections of other block devices. > The main goal of this driver is to support volume management in > general, not just for LVM. The kernel should provide general > services, not support specific applications. eg, The driver has no > concept of volume groups. The latest version being tested is at: ftp://ftp.sistina.com/pub/LVM2/device-mapper/device-mapper-0.90.02.tgz The tgz file contains a CVS snapshot which includes patches against 2.4.16 and some documentation (and details for the CVS repository). Currently there's a choice between an ioctl interface and a filesystem interface (dmfs). Example ======= To create a "logical volume" that concatenates /dev/sdc1 with /dev/sdd2: [units used below are 512-byte sectors] # cat > /tmp/lv1_table 0 1028160 linear /dev/sdc1 0 1028160 3903762 linear /dev/sdd2 0 ^D # dmsetup lv1 /tmp/lv1_table With the filesystem interface and devfs, you could also create /devfs/device-mapper/lv1 by hand as follows: # mkdir /tmp/dmfs; mount -t dmfs dmfs /tmp/dmfs # mkdir /tmp/dmfs/lv1 # cp /tmp/lv1_table /tmp/dmfs/lv1/table Striping is also already supported (see documentation). Alasdair -- agk@uk.sistina.com