Large page is a special purpose performance feature for memory objects. Authorized programs and unauthorized programs with read authority to facility class IARRSM.LRGPAGES can ask the system to use one megabyte page frames to back the memory object by using PAGEFRAMESIZE when issuing the IARV64 GETSTOR. Authorized programs might also request large pages for common memory objects using PAGEFRAMESIZE when issuing IARV64 GETCOMMON.
These large pages consume real storage and are non-pageable. The system programmer should carefully consider what applications are granted access to large pages. Not all applications benefit from using large pages. Long running memory intensive applications benefit most from using large pages. Short lived processes with a small memory working set are not good candidates. The system programmer defines the amount of real storage that can be used for large pages with the LFAREA system parameter. See IEASYSxx description in z/OS MVS Initialization and Tuning Reference.