If I use the move "nodedata>" command to move the primary copy >to the new storage pool and then back it up to the different copy >storage pool will the copy in the original copy storage pool be >automatically discarded? If not what is the best way to do this? > No, it will not automatically discard the old copy pool data.
The best way, and it's not a particularly good way, is to 'dev vol xxxxxx discarddata=yes' for the volumes in the old storage pool that had that node's data and then do a 'backup stg old_primary old_copy' to re-backup any other node data that was on the deleted tapes.