A backup of the stored data is not useful, because the data store is dynamically changing every few minutes. Each node’s reputation is based on auditing of the current data…
A backup data store will be missing any new data, as well as have extraneous data that was already deleted. The missing new data will cause a node restored from backup to become disqualified rather rapidly.
So, there will never be a method of backing up a Storj node data store. Such concepts do not apply to the nodes.