[CentOS] system "stuck" with 2.6.18-128 kernel. how to move to 2.6.18-194.17?

Sun Oct 3 20:24:45 UTC 2010
Phil Schaffner <Philip.R.Schaffner at NASA.gov>

Aleksey Tsalolikhin wrote on 10/03/2010 01:16 AM:
> Hi.  I just noticed I had a CentOS 5.3 system that I updated to CentOS
> 5.5 a few days ago,
> and I just ran "yum -y update" again to get the latest kernel, and I
> just noticed it still has the old 2.6.18-128 kernel instead of the new
> 2.6.18-194.17.  What gives?
> /etc/grub.conf points at 2.6.18-194.17, but when I reboot, 2.6.18-128 comes up.
> Any suggestions?

See what "cat /proc/mdstat" shows.  I suspect your RAID is degraded. 
The OS is seeing one member, and GRUB sees the other disk that is not 
currently being mirrored.