US Patent 9740426 Drive array policy control

An apparatus can include an interface; cache memory; a plurality of drives; and a controller that includes detection circuitry, a write through mode and a write back mode, where the write through mode writes information received via the interface to the plurality of drives, where the write back mode writes information received via the interface to the cache memory and writes information written to the cache memory to the plurality of drives, and where the detection circuitry selects the write through mode based at least in part on detection of a first condition and selects the write back mode based at least in part on detection of a second condition, where the first condition and the second condition differ.