Storage and retrieval of high importance pages in an active memory sharing environment

Using a set of non-volatile storage media and a virtual input/output system operating in a memory sharing environment, by: (i) estimating which non-volatile storage medium, of the set of non-volatile storage media, will have the fastest access at a given time; and (ii) read-writing (that is, reading and/or writing) data by the virtual input/output system of a high importance page to the non-volatile storage media estimated to have the fastest access time.