mdadm: Failed to assemble all arrays

[David Andel]

On Thu, 4 Mar 2010 09:04:53 +0100, martin f krafft <madduck at debian.org>
wrote:
> 
> In that case your most likely problem is that mdadm.conf is out of
> date. Use the output of /usr/share/mdadm/mkconf .
> 
> Try rootdelay=20 instead of =1.
> 
> If you are at the shell, can you assemble arrays with mdadm -A ?

Now I have a few more info on this:

When in Knoppix I can simply run:

root at Microknoppix:~# modprobe -k md
root at Microknoppix:~# /usr/share/mdadm/mkconf force-generate
root at Microknoppix:~# mdadm -A /dev/md1
mdadm: /dev/md1 has been started with 2 drives.
root at Microknoppix:~# 

Not so in initramfs. There 'mdadm -A /dev/md1' returns with 0 but no
device is being created.
I have to explicitly run 'mdadm -A /dev/md1 /dev/sd[ab]5'.
And then I cannot mount the generated device, as said before.

Interestingly, before I assembled only '/' on /dev/md1 and '/usr' on
/dev/md2 using the mdadm version in Knoppix.
Then I chrooted into that system (with binding /dev, /proc, and /sys to
the respective Knoppix equivalents).
The output of /usr/share/mdadm/mkconf in the chroot now differed in the
UUIDs from the /etc/mdadm/mdadm.conf generated before (using the same
version!).
With the stored version, I could not 'mdadm -A /dev/mdx' the arrays
differing in their UUID from the output described above.
I force-generated /etc/mdadm/mdadm.conf again.
Then I could assemble all arrays using -A.

Unfortunately, this did not change the behaviour in initramfs...

Do I have to 'modprobe -k md' there as well?
I didn't try that because I do 'insmod raid' and 'insmod mdraid' in
grub.cfg...