[CentOS] LVM VG disappears after kernel upgrade on 5.1

Fri Mar 7 06:07:45 UTC 2008
Ted Miller <tedjeanmiller at sbcglobal.net>

I finally got 5.1 to boot after install (install couldn't keep the disk IDs 
from getting crossed up, so at reboot partitions were not where install 
said they would be).

I needed to compile vmware and nvidia modules, but decided to upgrade 
first.  Told yumex to upgrade everything.

When I went to reboot the VG with / on it is not seen by the kernel.  (root 
partition is LVM on top of RAID 1).  If I go back to the old kernel 
everything boots fine.  On the new kernel only the VG on sdc is seen by LVM.

1. How do I persuade the new kernel to notice the VG with my root partition 
on it.

2. If #1 is not possible, how do I downgrade kernel-headers to the old 
version without having to uninstall the dependencies, so I can compile my 
kernel modules?

+ Original install was network install of 5.1/x86_64 from CD1 (of 7)
+ VGs were created under Centos 4.
+ VG DriveAB01 is on md1(sda5+sdb5) + md2(sda6+sdb6), only seen by
      original 5.1 kernel
+ /boot is on md0
+ VG DriveC01 is on sdc, and both kernels see it
+ hdd has Win2k on it for dual boot
+ hdb + hdc are DVD drives
+ hda is unused
+ Motherboard is Gigbyte k8n ultra 9
+ AMD 3500 Athlon 64 (single core)

Ted Miller
Indiana, USA