Can virtualization software manage server power consumption?

Tools like Microsoft's System Center can help admins manage virtual machines, but can they also improve server power consumption?

As IT budgets and staffing levels continue to tighten, organizations are watching operational costs more closely than ever. Business and technology administrators are making the most of virtualization in order to maximize efficiency and savings. This typically involves an array of virtualization-aware tools, such as Microsoft System Center, that can automate and dynamically adjust the computing environment as workload needs change.

Although the software tools used to automate and optimize server power consumption within a virtualized data center are constantly improving, they are far from being intuitive or adaptive -- software tools have no knowledge (and no practical way to determine) how your data center and its workloads should behave under every possible condition. Resource and power optimization features will require administrators to supply a selection of parameters that allow the software to make recommendations or automatic decisions.

First, administrators must decide whether the software tools will migrate workloads or control server power manually or automatically. In manual mode, the software will make recommendations but await administrator approval before migrating workloads or powering servers. And at the same time, the software must also know the resource thresholds (including processor, memory, disk space, disk I/O and network utilization) needed to make recommendations or take action.

Tools also need to know how aggressively to manage server power consumption, and System Center provides a basic slider that allows administrators to select Low, Medium or High aggressiveness which reflects the amount of improvement required to justify an optimization. More aggressive settings will look for more improvement before recommending (or triggering) a workload migration. Administrators must also decide how often to look for optimizations. Many organizations will consider optimizations every 10 or 15 minutes, reflecting the changeable nature of modern data centers.

If tools also optimize server power consumption, administrators can decide whether to enable or disable the feature, and select a schedule for running power optimizations (usually during off hours like overnight or on weekends). When outside of the schedule (such as peak hours like weekdays), power optimization is typically disallowed and all servers are powered up and rebalanced to handle the day’s computing. Power optimization is usually configured so that unexpected increases in activity will still allow servers to power on in order to meet additional computing needs.

Next Steps

Understanding C-state and P-state can cut server power consumption

How to calculate power savings from virtualization

Dig Deeper on Green data center: Reducing power consumption with virtualization