Performance of SAP ERP with memory virtualization using IBM Active Memory Expansion as an example

Main memory virtualization is used to expand the effective main memory capacity meaning that more virtual main memory is represented to guest operating systems than physical memory is actually available. This is done by compressing and uncompressing memory pages. Obviously the price for main memory virtualization is a higher CPU utilization, especially when dealing with high workloads. SAP ERP systems represent the backbone of today's enterprises and have a very high resource demand. The combination of main memory virtualization and SAP ERP system is of great importance but has not yet been thoroughly researched. This paper is the first approach to a quantitative research for evaluating the performance impact of memory virtualization on SAP ERP systems. We utilize a synthetic main memory benchmark, called Zachmanntest, to evaluate the performance impact of main memory virtualization on a SAP ERP system. As an exemplary main memory virtualization implementation IBM's Active Memory Expansion is used, where a so called expansion factor can be used to specify the size of the virtual main memory. Performance results show that the greater the expansion factor, the greater the performance impact. Regarding the peak performance, throughput of SAP ERP systems may be decreased till -17%, whereas the overall throughput of such systems may experience a decrease up to -42% when dealing with a very high compression factor.