Regions in WSAF Caching exist to allow a set objects to be searched by tag. This search functionality requires all objects to be stored on a single cache host, and regions are used to keeps these objects together.
Objects do not need to be grouped together on the same ScaleOut StateServer host if you want to search for them by tag—ScaleOut StateServer is able to perform a distributed query across all objects in all hosts that are part of the distributed data grid. Regions, therefore, are neither needed nor supported—there are no API calls that require a region to be specified.
