[Yaird-devel] Booting fails after moving to another hardware: unable to find root partition

[Jonas Smedegaard]

On Tue, 21 Mar 2006 23:08:50 +0100
Reiner Benedikt Nix <reiner.nix at web.de> wrote:

> Problem for using dpkg-reconfigure: as on the new hardware the system
> is yet not running, regeneration cannot determine the targent
> hardware and vice versa :-(

Sorry that I did not pay enough attention to your scenario: Yaird does
not generate a general purpose ramdisk that you can transfer to another
host and it will magically work. For "magical" ramdisks, please use
initramfs-tools instead.

What you can do with yaird is explicitly load some modules in addition
to the ones automatically detected, and override the mount routine with
some homebrewn stuff. Neither of that is interesting if you don't know
ahead what you will need on your future host, however - then you need
magic which is oart of initramfs-tools design but not yaird.


> Fo me it was sufficient to regenerate the initial ram disk manually.
> Of course I need the SATA driver to access the hard disk. Otherwise
> it seemed to be enough to just changing the root partition name.
> Funtunately, the generated initial ram disk has a very clear
> structure, so applying the change could be done easily.
> 
> It would be nice, if the root partition name passed as boot parameter
> could be used. This would be helpfull as I use to make copies of the
> root partition for backup purpose, regularly on the same hardware but
> on another hard disk.

Knowing the root device name is not enough. The device also needs to be
created, and chains of modules needs to be loaded.

Yaird resolves dependencies _before_ boot, include only modules really
needed to get the rootfs, and generate custom shell code to do so, to
keep the ramdisk as small as possible.

As comparison, initramfs-tools includes a bunch of modules, includes
udev on the ramdisk and rely on that to do the resolving at boot time.


It would indeed be great for yaird to have more flexibility, but it
sounds like what you want is exactly the behaviour of initramfs-tools,
and I don't think it is relevant nor interesting to change yaird into
behaving like initramfs-tools.


I am interested in concrete suggestions to have yaird support rootfs
passed on at boot time, while preserving its fundamental logic of
staying minimal and being smart at build time rather than at boot time.

 - Jonas

-- 
* Jonas Smedegaard - idealist og Internet-arkitekt
* Tlf.: +45 40843136  Website: http://dr.jones.dk/

 - Enden er nær: http://www.shibumi.org/eoti.htm
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