> Usually indicates missing storage driver in initramfs (if you were on > VMware, I would tell you to check if vmw_pvscsi.ko is present in > initramfs).
First thing to check would be to compare the list of PCI devices (lspci) and storage devices (cat /proc/partitions) between the older and the newer kernel. Also, check dmesg for any errors. If that doesn't work, try to boot into a rescue system, mount the rootfs, chroot, then regenerate the initrd. I've found that the update process in CentOS fails sometimes, rendering the system unbootable. Regenerating the initrd or reinstalling the kernel package usually helps.
