Odd booting problem

[maurice <mhilarius@gmail.com>]

Good day all, and Happy Thanksgiving for those in Canada!

An odd problem, and hopefully someone reading this can tell me what to 
do differently:

I am converting a machine from a single disk to one with 2 disks and 4 
md RAIDs.

I do not know how much detail people might like, so I will keep it as 
terse as possible to start:
Original install CentOS 6.0, with all updates.
XC86_64 kernel

mdadm v3.2.2

I have added the second physical disk, and duplicated the partition 
table from the existing system disk
created 4 md RAID1s, to be used for /boot, /, /var, and /home
All were created with the second part missing:
mdadm --create /dev/md0 --metadata=0.90 --level=1 --raid-disks=2 
/dev/sda1 missing
mdadm --create /dev/md1 --level=1 --raid-disks=2 /dev/sda2 missing
mdadm --create /dev/md2 --level=1 --raid-disks=2 /dev/sda5 missing
mdadm --create /dev/md3 --level=1 --raid-disks=2 /dev/sda6 missing

System is booting on GRUB 0.97.
Therefore I made the md0 ( /boot) with 0.90
And then made md1, md2 and md3 with 1.2

Everything looks good in /proc/mdstat
I made file systems ( ext for boot and ext for others) , then copied 
over all data from original disk.

Created the mdadm.conf file:
mdadm --detail --scan > /etc/mdadm.conf

I used dracut to rebuild the initramfs with the new mdadm.conf:

dracut --mdadmconf --force /boot/initramfs-$(uname -r).img $(uname -r)
This completed uneventfully.

Edited /etc/fstab and rebooted.
Now I have all my filesystems on the md devices with no complaints.

Ran grub and installed on the new disk :
root (hd0,0)
setup (hd0)
Completed successfully

Next, rebooted again, and this time manually edited the grub command 
line to change
from root=/dev/sdb2  to root=/dev/md1

And here it gets funny:

Boots a bit, then I see:

dracut Warning: No root device "block: /dev/md1" found.

And a few seconds later we get a kernel panic.





-- 
Cheers,
Maurice Hilarius
eMail: /mhilarius@gmail.com/