tunefs -L issue

[Steve Franks]

I'm seeing this in my dmesg:

GEOM: ad0s1: geometry does not match label (255h,63s != 16h,63s).

I'm guessing I screwed up tunefs -L, but it sure looked
straightforward.  Anyway, my /dev/ufs is empty, and I kind of thought
there should be stuff in it.  I called tunefs -L from single-user
mode, so usr, var, and tmp should have been unmounted as per
instructions.

If I start playing with the "geomerty", am I going to wipe my system
inadvertently?

Also, I kind of think the ufsid is really what I'm looking for, and
/dev/ufsid is empty too!  Isn't this the class of things that should
"just work"?  I mean, the disk is pretty fundamental.  I swap disks in
and out alot, and I've got one of those motherboards that likes to
reorder them, making booting reliably under 8-RELEASE a real pain in
the neck...

Best,
Steve