From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756649AbZGVJE2 (ORCPT ); Wed, 22 Jul 2009 05:04:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756643AbZGVJE0 (ORCPT ); Wed, 22 Jul 2009 05:04:26 -0400 Received: from mail-fx0-f218.google.com ([209.85.220.218]:32820 "EHLO mail-fx0-f218.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756311AbZGVJEZ convert rfc822-to-8bit (ORCPT ); Wed, 22 Jul 2009 05:04:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type :content-transfer-encoding; b=tNMv7IOHwD+ZqlzONyrgcMs2eqn09NKz8xu9LCRXkJaGGNesBH6ZaGDNZsIuQd1B9b Y6jXBnDkYgUMv+8a9Bu/+N1eueC84hgIstyS2YdrW6935yJAN3iwdY8wv9xh/8oyjMM0 CG8RDE406+WqE/h9u7l75OcTByigdspw6Iyq8= MIME-Version: 1.0 Date: Wed, 22 Jul 2009 10:04:23 +0100 Message-ID: <66781b10907220204o26964a70j90348ec78a685b52@mail.gmail.com> Subject: RAID60 - MD / LVM From: mark delfman To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, Firstly let me apologise for what maybe a simple question, I have tried to google and search this out. The question is simply ‘the best way to create a RAID60 or any nested RAID’.  Looking at the examples it seems the approach is to create 2 x RAID6’s and then simply RAID0 on top.  However, is there any advantage in using MD to create the RAID0 or would you see the same overall result by using LVM to stripe (R0) the 2 x RAID6’s? Given that I see a lot of post’s RE: RAID10, then I ‘suspect’ that the MD RAID0 code has some understanding of or tuning for nested RAID’s, which I guess LVM may not have. It would seem the answer is obvious as it makes sense to simply use MD, but we have an internal system based on 100’s of old scripts and the RAID section only allows us to select  ‘drives’ (not raids), it does however use LVM so it would be easier to change the script which created the VG as opposed to change the many scripts related to RAID creation... If there is a real disadvantage in using LVM, then we can manually create the RAID’s I guess.... I would appreciate any feedback