Method and apparatus for application profiling in a multi-device data storage array. In accordance with various embodiments, a storage array is formed of independent data storage devices that form a fast pool and a slow pool of said devices, such as solid-state drives (SSDs) and hard disc drives (HDDs). A controller is adapted to migrate a distributed data set stored across a first plurality of the devices in the slow pool to a second plurality of said devices in the fast pool. The controller carries out the migration responsive to a hint that a selected application is about to be executed that utilizes the distributed data set, and responsive to a return on investment (ROI) determination that an estimated cost of said migration will be outweighed by an overall improved data transfer capacity of the storage array over a predetermined minimum payback period of time.