Paging data sets

Paging data sets and optional storage-class memory (SCM), contain the paged-out portions of all virtual storage address spaces. In addition, output to virtual I/O devices may be stored in the paging data sets. VIO data cannot be stored on SCM because SCM does not currently support persistence across IPLs. Before the first IPL, you must allocate sufficient space to back up the following virtual storage areas:

Primary storage for the pageable portions of the common area
Secondary storage for duplicate copies of the pageable common area
The paged-out portions of all swapped-in address spaces - both system and installation
Space for all address spaces that are, or were, swapped out
VIO data sets that are backed by auxiliary storage.

Note: VIO data must remain on page data sets even when SCM is installed. All other data types can be paged to page data sets or to SCM.

Paging data sets are specified in IEASYSxx members of SYS1.PARMLIB. When this is done, any PAGE parameter in an IEASYSxx specified during IPL overrides any PAGE parameter in IEASYS00. For paging to SCM, use the PAGESCM IEASYSxx member.

To add paging space to the system after system installation, the installation must use the access method services to define and format the new paging data sets. To add the new data sets to the existing paging space, either use the PAGEADD operator command or reIPL the system, issuing the PAGE parameter at the operator's console. To delete paging space, use the PAGEDEL operator command. To bring additional SCM online after an IPL, use the CONFIG ONLINE command.

During initialization, paging spaces are set up by merging the selected IEASYSxx parmlib member list of data set names with any names provided by the PAGE parameter (issued at the operator console) and any names from the previous IPL.