Paging

Main memory management is characterized by the paging mechanism, which allows the efficient use of a relatively small main memory in relation to the virtual address space requirements.

Because paging both causes time delays and adds to the workload on the processor and the disk peripherals, the paging rates specified in section "Standard values for BS2000 servers" should not be exceeded.

You should also make sure that a sufficient number of volumes is available for performing the paging I/O operations. Around 30 paging I/O operations per second can be implemented for each volume (given a workload of 10% and a read hit rate of 70%).

Clues as to the cause of the paging rate are provided by the ratio of the memory used by the system (SWS) to the number of main memory pages available for paging (NPP).

See also the notes on "Reports "Page frames" of the report group MEMORY and "Main memory utilization" of the report group WORKING-SET".

The tables in the section "Standard values for BS2000 servers" contain representative main memory configurations for various servers. The actual main memory required depends on the workload. TP and interactive loads usually have a considerably higher main memory requirement than batch loads.