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From: "Ortwin Glück" <odi@odi.ch>
To: Drew DeVault <sir@cmpwn.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Failover root devices
Date: Thu, 17 Sep 2015 13:40:43 +0200	[thread overview]
Message-ID: <55FAA6BB.3060008@odi.ch> (raw)

 > 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


             reply	other threads:[~2015-09-17 11:40 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-17 11:40 Ortwin Glück [this message]
2015-09-17 11:49 ` Failover root devices Drew DeVault
2015-09-17 17:47   ` Richard Weinberger
2015-09-17 17:49     ` Drew DeVault
2015-09-17 17:52       ` Richard Weinberger
2015-09-17 18:05         ` Drew DeVault
2015-09-17 18:17           ` Richard Weinberger
2015-09-17 18:18             ` Drew DeVault
2015-09-17 18:19               ` Richard Weinberger
2015-09-17 18:21                 ` Drew DeVault
2015-09-17 18:23                   ` Richard Weinberger
2015-09-17 18:28                     ` Drew DeVault
2015-09-18 14:59                       ` Ortwin Glück
2015-09-18 15:00                         ` Drew DeVault
2015-09-18 15:04                           ` Ortwin Glück
2015-09-18 15:36                             ` Austin S Hemmelgarn
2015-09-17 18:27             ` Harald Hoyer
2015-09-17 18:29               ` Drew DeVault
2015-09-17 18:33                 ` Richard Weinberger
2015-09-17 18:35                   ` Drew DeVault
2015-09-17 18:42                     ` Richard Weinberger
2015-09-17 18:29               ` Richard Weinberger
2015-09-17 18:37     ` Austin S Hemmelgarn
2015-09-17 18:40       ` Richard Weinberger
2015-09-18 14:40         ` Austin S Hemmelgarn
  -- strict thread matches above, loose matches on Subject: below --
2015-09-17  0:16 Drew DeVault
2015-09-17 16:02 ` Austin S Hemmelgarn
2015-09-17 17:30   ` Drew DeVault
2015-09-18 14:34     ` Austin S Hemmelgarn
2015-09-18 14:43       ` Drew DeVault

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