Westmere-EX: Intel's Flagship Benchmarked

vApus Mark II

vApus Mark II is our newest benchmark suite that tests how well servers cope with virtualizing "heavy duty applications". We explained the benchmark methodology here. We used vSphere 4.1 Update 1, based upon the 64 bit ESX 4.1.0 b348481 hypervisor.

* with 128GB of RAM

Benchmarks cannot be interpreted easily, and virtualization adds another layer of complexity. As always, we need to explain quite a few details and nuances.

First of all, we tested most servers with 64GB of RAM. However, the memory subsystem of the Quad Xeon needs 32 DIMMs before it can deliver maximum bandwidth. As some of these server systems will get those 32 DIMMs while others will not, we tested both with 16 (64GB) and 32 DIMMs (128GB). Our vApus mark test requires only 11GB per tile: 4GB for the OLTP database, 4GB for the OLAP and 1GB for each of the three web applications (3GB in total). So even a five tile test demands only 55GB. Thus, in this particular benchmark there is no real advantage to having 128GB of RAM other than the bandwidth advantage for the quad Xeon platform. That is why we do not test the the Quad Opteron with more than 64GB: it makes no difference and makes the graph even more complex.

Then there's the problem that every virtualization benchmark encounters: the number of tiles (a tile is a group of VMs). With VMmark, the benchmark folks add tiles until the total throughput begins to decline. The problem with this approach is that you favor throughput over response time. In the real world, response time is more important than throughput. We test with both four (20 VMs, 72 vCPUs) and five tiles (25 VMs, 90 vCPUs). Which benchmark gives you the most accurate number for a given system? Let us delve a little deeper and take the response time into account.