VMware published a paper which shows that vSphere 4.1, out of the box, easily supports a demanding SAP ERP installation by allowing administrators to either scale up or scale out.
Scaling up by Adding Processors
To test scale-up performance, we used similarly configured physical and virtual machines to see how many SAP users could be supported with one, two, four, and eight processors.
Figure 1. Number of users supported while scaling up virtual and physical (native) CPUs
In the experiments, a virtual machine with 8 vCPUs was able to support approximately 1,200 users, achieving 93%-95% of the number of users as a similar native test.
Scaling out by Adding Servers
vSphere 4.1 can be scaled out to support larger user workloads. We ran a series of tests with multiple virtual machines to compare the performance of different scale-out scenarios with SAP. The following graph shows the scale-out test results and is highlighted by 16-vCPU tests. These tests show that approximately 2,500 SAP users can be supported using four virtual machines each with 4 vCPUs, or 8 virtual machines each with 2 vCPUs (for a total of 16 vCPUs in both cases).
Figure 2. Scale-out test with 2- and 4-way VMs
The test results for both scaling up and scaling out show that vSphere 4.1 provides good performance for SAP in a variety of environments.
To read the full paper, see SAP Performance on vSphere with IBM DB2 and SUSE Linux Enterprise.