Re: kernel/initrd and rootfs over LVM

[Valdis . Kletnieks]

On Thu, 23 Oct 2003 13:44:25 -0300, Flavio Bruno Leitner <fbl@xxxxxxxxxxxxxxxx>  said:
> 
> I'm using kernel 2.6.0-test7 and as far I understand 
> prepare_namespace() checks if saved_root_name[0] is
> not null (I'm passing root=/dev/vg0/lvroot), then
> name_to_dev_t() try to guess what MINOR and MAJOR 
> are used by the root device. 

What I ended up doing to get that working back in the 2.5.4x days was to have
my initrd's linuxrc do a 'lvm vgscan' to get the volume group online, and then
an 'lvdisplay' - this of course wedged up after it since there wasn't a proper
root=, but it revealed the numbers I needed.

As far as I can tell, if you're using the device-mapper in 2.6, you'll want
MAJOR=, and then the MINOR= seems to be stable across 2.4/2.6/lvm1/lvm2 (So if
you're building the system under 2.4 and have LVM running there, you can get
the minor number from lvdisplay there, and use it with major=254 to get your
2.6 up and running.  For lilo, I ended up using this:

        root=65029
# magic number is major=254 * 256 + minor=5

Grub you're on your own.  Yes, I should upgrade, but lilo *does* work for this machine, sooo.

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