From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750792AbWATP2p (ORCPT ); Fri, 20 Jan 2006 10:28:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750788AbWATP2p (ORCPT ); Fri, 20 Jan 2006 10:28:45 -0500 Received: from eurogra4543-2.clients.easynet.fr ([212.180.52.86]:31964 "HELO briare1.heliogroup.fr") by vger.kernel.org with SMTP id S1750795AbWATP2o (ORCPT ); Fri, 20 Jan 2006 10:28:44 -0500 From: Hubert Tonneau To: neilb@cse.unsw.edu.au Cc: linux-kernel@vger.kernel.org Subject: RE: [PATCH 000 of 5] md: Introduction Date: Fri, 20 Jan 2006 16:48:36 GMT Message-ID: <0610HD112@briare1.heliogroup.fr> X-Mailer: Pliant 94 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Neil Brown wrote: > > These can be mixed together quite effectively: > You can have dm/lvm over md/raid1 over dm/multipath > with no problems. > > If there is functionality missing from any of these recommended > components, then make a noise about it, preferably but not necessarily > with code, and it will quite possibly be fixed. Chiepest high capacity is now provided through USB connected external disks. Of course, it's for very low load. So, what would be helpfull is let's say have 7 usefull disks, plus 1 for parity (just like RAID4), but with not a result of one large partition, but with the result of seven partitions, one on each disk. So, in case of one disk failure, you loose no data, in case of two disks failure, you loose 1/7 partition, in case of three disks failure, you loose 2/7 partitions, etc, because if the RAID4 is unusable, you can still read each partition as a non raid partition. Somebody suggested that it could be done through LVM, but I failed to find the way to configure LVM on top of RAID4 or RAID5 to grant that each partition sectors are consecutive all on a single physical disk.