If you lose a disk or the whole system, you can externally restore data only if it was externally backed up. You must use the same third-party utility for both the external backup and restore. To externally restore the storage spaces, copy the backed up data to disk. Use the ontape -p -e command to mark the storage spaces as physically restored, replay the logical logs with the ontape -l command, and bring the storage spaces back online. If you do not specify an external restore command, the database server cannot update the status of these storage spaces to online.
You can only perform a cold external restore with ontape. A cold external restore marks storage spaces as physically restored, then performs a logical restore of all storage spaces.
To salvage logical logs, perform ontape -S before you copy the external backup and perform the external restore (ontape -p -e).