>   I'm also wondering if there's a good description of the magic that  
> needs to be performed on each disk individually so that the openboot  
> prom will be able to boot from either of them.  Anything more  
> complicated required than the "make sure both disks labels are the  
> same, and run installboot for each" step(s) described in:
> 
> http://www.netbsd.org/docs/guide/en/chap-rf.html

Yep, just run installboot on both disks.  I useually try and boot into (at
least) single-user mode on both disks just to be sure.  Also, you can set
multiple entries for the "boot-device" PROM field.  I have mine set to
"boot-device=disk:a disk1:a", so that it should automatically boot from the
2nd disk if the first one has failed.  Note, that this doesn't help if the
1st disk has an incomplete boot loader install, as the PROM will succeed
but the boot will fail later.

J

-- 
  My other computer also runs NetBSD    /        Sailing at Newbiggin
        http://www.netbsd.org/        /   http://www.newbigginsailingclub.org/