ZFS pool broken after upgrading to 14.04 LTS
Solution 1:
The problem is that after the upgrade zfs thinks that this is a different server. You should be able to fix it by simply exporting and then importing the pool.
sudo zpool export naspool1
sudo zpool import naspool1
Most likely the import will complain that the "pool may be in use by another system, use -f to import it anyway". Use -f to do the import:
sudo zpool import naspool1 -f