Fixing vdev name

[David Chisnall]

Hello the list,

I have a VM that uses ZFS with a pair of striped devices.  The first is 
a partition on the root disk, created by the installer.  When this was 
too small, I added another device (da1) and told the pool to expand to 
use it (no redundancy, because the underlying storage for the VM images 
provides that).  After a reboot, I can no longer boot the system. 
Booting from the install CD and attempting to import the pool, it 
correctly identifies da0p4 as one of the devices, but gives me a long 
number instead of da1.

How do I fix this so that the pool again points to da1?

David