[CentOS] ERROR MESSAGE: dracut warning: no root device "block:/dev/mapper/vg_ws194-lv_root" found

> mv /boot/initramfs-2.6.32-358.0.1.el6.i386.img /boot/initramfs-2.6.32-358.0.1.el6.i386-nouveau.img
> dracut /boot/initramfs-2.6.32-358.0.1.el6.i386.img 2.6.32-358.0.1.el6.i386
> 
> Interestingly enough, the new initramfs that I got from this command is slightly
> smaller than the one that I already had in /boot.
> 
> Sadly, this made no difference.   When I booted the machine, I still got the
> same dracut warning and kernel panic.
> 

To me looks like the initramfs does not contain all the needed "pieces" to boot
the machine.

Try investigating the dracut options to include more modules or filesystem etc.
starting with --lvmconf and --mdadmconf