US Patent 9081683 Elastic I/O processing workflows in heterogeneous volumes

The present disclosure provides advantageous methods and systems for input/output processing workflows in a heterogeneous data volume. One embodiment relates to a method of writing data to a heterogeneous data volume having multiple disk classes of storage. A class of storage tier for the data write is selected using operating modes for the tiers, where the operating mode for a tier instance depends on statistical measures of operating parameters for that tier. One operating mode is an elastic mode, where the chance that a tier instance is selected may vary depending on a statistical measure of an operating parameter in relation to lower and upper threshold values. Other embodiments, aspects and features are also disclosed.