1. A method of destage management of redundant data copies in a cache storage subsystem, comprising: providing a plurality of target storage devices, each of the plurality of target storage devices capable of storing a complete copy of a data image; subdividing the data image and the target storage devices into a plurality of sub-regions, each of the plurality of sub-regions organized such that a minimum cumulative total of the plurality of sub-regions on the target storage devices equals a number of sub-regions required to reconstruct the complete copy of the data image; and destaging data from a write cache to the plurality of sub-regions on the target storage devices in an order such that a minimum number of sub-regions can be combined to restore the complete copy of the data image in a minimal elapsed time, wherein: the order is structured such that data from one of the plurality of sub-regions is destaged to a first of the plurality of target storage devices in parallel with data from another one of the plurality of sub-regions destaged to a second of the plurality of target storage devices.