RAID related bug: Freshly installed OpenSuse 13.1 hangs at booting (fix included)

If you set up OpenSuse 13.1 using a named software RAID volume as root volume, it will hang and lock up when Yast reboots (usually after the online update).

If one presses ESC to see the console output, one can notice that the boot fails with this message:

After this message, the system spams you with the suggestion to log in and do a "journalctl -xb" to analyze the problem.
But as it only responds to the reset button, you can neither log in nor finish the installation, as it gets stuck the same way at the next boot.

To get around this bug you have to do these steps:

1. Boot the rescue system from the install DVD.

2. After logging in as root, enter the following command:
Now you know which md device is your root filesystem.

2a. If you aren't sure which one is the root filesystem, examine each of the md volumes by

for each of the md device numbers which are counting down from 127, by replacing XXX with the md number.

3. Mount the root filesystem using

(Insert the md number of the root filesystem for XXX.)

4. Fix the problem by entering

5. Reboot:

6. Continue and finish installation.


This is an old bug of the 13.1 RC install scripts which made it into the final release.
See http://lists.opensuse.org/opensuse-b.../msg01501.html
Apparently many people ran into this problem, and end up not using RAID, at least not for the root filesystem, or even switch to another distro.
So I hope this post helps others who stumble into that issue too.