Auxiliary storage management initialization

This topic describes the effective initialization and use of paging, which can use page data sets only, or page data sets in addition to optional storage-class memory (SCM).

Paging is the process that z/OS® uses to select which pages to move from central storage to auxiliary storage. Auxiliary storage requires page data sets on DASD, and can also include the optional SCM on Flash Express® (SSD) cards. If SCM is available and online, ASM uses both SCM and page data sets for auxiliary storage by paging data to the preferred storage medium, based on response times and additional factors.

Adding SCM to your system can increase the flexibility and performance of your paging operations. However, because SCM is not persistent across IPLs, SCM cannot be used for paging Virtual I/O (VIO) data or PLPA data for warm starts.

For additional information on ASM, refer to Auxiliary storage overview, and the PAGE, PAGESCM, NONVIO and PAGTOTL parameters of parmlib member IEASYSxx in z/OS MVS Initialization and Tuning Reference.