Dear Sebastian,

thanks for your valuable response.

Am Mittwoch, 30. Januar 2013, 10:07:24 schrieb Sebastian Riemer:

On 29.01.2013 23:14, Hans-Peter Jansen wrote:
[...]

quoted

~# cat /proc/mdstat
Personalities : [raid1] [raid0] [raid10] [raid6] [raid5] [raid4]
md3 : active raid1 sda4[0]

      869702736 blocks super 1.0 [2/1] [U_]
      bitmap: 57/415 pages [228KB], 1024KB chunk

md0 : active raid1 sda1[0]

      96376 blocks super 1.0 [2/1] [U_]
      bitmap: 1/6 pages [4KB], 8KB chunk

md1 : active (auto-read-only) raid1 sdb2[1] sda2[0]

      2096468 blocks super 1.0 [2/2] [UU]
      bitmap: 0/8 pages [0KB], 128KB chunk

md124 : active raid1 sdb3[1] sda3[0]

      104856180 blocks super 1.0 [2/2] [UU]
      bitmap: 8/200 pages [32KB], 256KB chunk

This looks like some kind of race during device detection.
The full boot sequence log leading to this mess is attached.

[...]

quoted

Could some kind soul tell me, what's going on here?

Funny, we've observed similar strange behavior when putting MD devices
on iSCSI/SRP exports. We connect to the SCSI target and udev does lots
of crap assembling only 1/2 or even 0/2 devices. This is why we disable
all udev rules related to MD and do it by custom scripts.

Oh, I see. Forgot to mention, I do not enjoy fiddling in mkinitrd code ;-)  
(been there, had to do that for my aufs2 based diskless setups)

In mdadm 3.2.6 a possible fix has been introduced.

Check: git log mdadm-3.2.5..mdadm-3.2.6


commit 090900c3d2eb5b3aef5251a21228483c32246cc7
Author: Harald Hoyer [off-list ref]
Date:   Mon Aug 13 08:00:21 2012 +1000

    udev-rules: prevent systemd from mount devices before they are ready.

commit b7e05d2373313dd8d0cb687479ad58a88f37d29f
Author: NeilBrown [off-list ref]
Date:   Thu May 24 11:49:49 2012 +1000

    udev-rules: prevent systemd from mount devices before they are ready.


Does mdadm 3.2.6 solve this?

Hmm, according to mdadm from openSUSE:12.1:Update, the relevant fixes should 
be in place. It might be an unfortunate combination of this issue and the 
asynchronously applied updates, interfered by the *switching* behavior. 

I started with regenerating the initrds now, and a first reboot succeeded so 
far. Good.

Will ask my friend to reboot the system a dozen times tonight.

Thanks,
Pete