Bruce Herndon does some scaling tests with VMmark on a HP DL380G5 server with the new Intel Woodcrest dual-core processors. The different workloads (mail server, java server, database, web
server, and file server) have different scaling characteristics,
depending on their need for CPU, memory, disk, and network capacity. He also looks at the scaling of realistic workloads looks two different configurations: six disks in a single LUN, and two three-disk LUNs.
These two different disk configurations highlight some interesting tradeoffs and tuning opportunities exposed by VMmark. The single LUN configuration utilizing six disks has the benefit of providing high disk throughput for one VM at the expense of scalability if multiple disk-intensive VMs are running. On the other hand, creating multiple LUNs provides both good predictability and excellent scaling but limits the total throughput of any single VM by providing only a subset of the hardware resources to each one. From a benchmarking perspective, the multi-LUN approach is clearly better since it results in a higher overall score. In practice, the proper approach depends upon the needs and goals of each user. I am excited by the ability VMmark gives us to study these types of performance tuning tradeoffs in a representative multi-VM environment. I feel that building performance tuning expertise in these complex situations and getting that information to our customers along with the ability to evaluate hardware and software platforms for virtualization should make VMmark an extremely valuable tool. Please stay tuned as we work to make that a reality.
Despite some claims to the contrary, VMmark is available to beta testers now (email firstname.lastname@example.org), and will be released for general availability.