z/VM Large Memory - Linux on System z

This report analyzes the results observed with Linux guests running a database server under online transaction processing (OLTP) workload in a z/VM environment using a relatively large amount of main memory (80 GB). Additionally, the amount of virtual memory was increased to use two times more virtual memory than physically available (memory overcommitment).

Published December 2007

To test the z/VM memory management behavior, the impact of the following z/VM memory management features was tested:

• VM Resource Manager Cooperative Memory Management (VMRM-CMM), initially available with z/VM 5.2 (also known as CMM Version 1)
• Collaborative Memory Management Assist (CMMA), initially available with z/VM 5.3 (also known as CMM Version 2)

These features were expected to improve the overall system performance in cases where the overall z/VM system is constrained for real storage.