From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752049AbbIQLkc (ORCPT ); Thu, 17 Sep 2015 07:40:32 -0400 Received: from fep26.mx.upcmail.net ([62.179.121.46]:53641 "EHLO fep26.mx.upcmail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbbIQLk1 (ORCPT ); Thu, 17 Sep 2015 07:40:27 -0400 X-SourceIP: 77.58.229.21 X-Authenticated-Sender: odi.ch@hispeed.ch To: Drew DeVault , "linux-kernel@vger.kernel.org" From: =?UTF-8?Q?Ortwin_Gl=c3=bcck?= Subject: Re: Failover root devices Message-ID: <55FAA6BB.3060008@odi.ch> Date: Thu, 17 Sep 2015 13:40:43 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I would like to see Linux support multiple root devices You can do that completely in user space from an initramfs. From your init script you can do what you want. You may even parse /proc/cmdline and use the root= parameter as you propose. Then mount whatever root device you want by whatever method you like and finally exec switch_root /mnt/root /sbin/init "$@" See here for example scripts for initramfs: http://www.linuxfromscratch.org/blfs/view/svn/postlfs/initramfs.html Above script actually makes it easy by supporting disk labels: root=LABEL=ROOT will boot the first available partition that is labelled ROOT. It is independent of the device name and works nice when you switch hardware vs. virtual machines for instance. Ortwin