Each disk drive in an array includes a housing that encloses a motor and at least one magnetic disk. The housing also encloses first and second actuators each with respective first and second heads that independently access the magnetic disk. The first actuator is mapped to a first logical unit and the second actuator is mapped to a second logical unit. A host interface of each disk drive facilitates access to the first and second logical units. A system includes a first storage controller attached to all of the first logical units as a first active server and attached to all of the second logical units as a first passive server. A second storage controller operates redundantly with the first storage controller. The second storage controller is attached to all of the second logical units as a second active server and attached to all of the first logical units as a second passive server.