[CentOS] "Can't find root device" with lvm root after moving drive on CentOS 6.3

Sat Mar 23 03:33:00 UTC 2013
Barry Brimer <lists at brimer.org>

> When I booted the box after this, I got a kernel panic, the typical
> "Can't find root device".

> Reading https://fedoraproject.org/wiki/How_to_debug_Dracut_problems , I
> did the following:
>
> # lvm vgscan
> # lvm vgchange -ay
>
> And then
>
> # ln -s /dev/mapper/<volumegroup>-<root_volume> /dev/root
> # exit
>
> After this, the box boots up normally, and everything works as it
> should. However, when I reboot, it again fails to find the root device.
>
> So, after all this, my question is, how do I make Dracut (I'm assuming)
> understand that this LVM volume is my root device and pick it up
> automatically?

What does your kernel line in grub look like?

Barry