"James K. Lowden" writes:
[snip]
> A friend helped me by pointing out that "boot -a" prompts for the root
> file system device.  That got me back up and running.  Hallelujah!

Right.

> Two questions, please:
> 
> 1.  Where does raidctl(8) store its information?  I'm guessing the boot
> blocks, because that's where the kernel learns its root device.  

No.  Each RAID component has its own, private "component label".
These are not the bootblocks, nor the disklabel.

> 2.  How to set the root device back to wd0a?  It might be that I used
> "raidctl -A root raid0" at some point (mistakenly).  Is "raidctl -A yes
> raid0" sufficient?  

Yes.  "raidctl -A root raid0" tells RAIDframe to treat raid0 as 
though it were the boot device, and then RAIDframe does some 
Ugly Stuff to override what the kernel thinks was the boot device. 
"raidctl -A yes raid0" will have raid0 autoconfigure, but not be 
a boot/root device.  It's what you most certainly want for a 
/usr/local partition.

Later...

Greg Oster