Implementations generally relate to storage systems. In one implementation, a system includes a plurality of storage libraries that store a plurality of removable media units. The system also includes a plurality of head units for reading and writing to one or more of the removable media units. The system also includes a plurality of robots that transfer one or more of the removable media units between one or more of the storage libraries and one or more of the head units. The system also includes enabling one or more of the robots to recover a set of data from two or more of the removable media units if a failure occurs in association with at least one of the other removable media units.