Oracle Database Scalability in VMware ESX

Database workloads are often provisioned on systems with much higher CPU and memory configurations than required by their average utilization. This is most commonly driven by the need for “headroom”—because database workloads are hard to migrate to a larger system, administrators often select a system much larger than immediately required in order to ensure that there will be sufficient capacity for peak portions of the workload and to allow for future growth. As a result, the utilization of dedicated database systems is often less than 20 percent of available CPU. For example, when studying over 2,000 four‐way Oracle database instances, the average utilization was found to be 4.92 percent (from data captured by VMware Capacity Planner, June 2006). In addition, today’s multisocket, multicore systems, with high memory capacity and bandwidth, multiple high‐speed network connections, and numerous high‐performance storage options provide computing resources that are difficult to fully utilize with a single database instance. As a result, there is ample opportunity to consolidate several database instances onto a single server.