Examples
Worked examples
- Is an instance
A cluster consolidates idle login nodes overnight to a single host, exploiting energy proportionality.
- Is an instance
A research group migrates from dedicated workstations to a shared compute service with higher average utilisation.
Counter-examples
Looks similar, but isn't
- Not an instance
A server that draws 200 W idle and 220 W under load is non-proportional.
- Not an instance
Always-on legacy hardware kept running just in case is the opposite.
Editorial commentary
Coined by Barroso and Holzle (2007), energy proportionality is a design property in tension with the historic reality that many servers draw 50 to 70 percent of peak power even at low utilisation. Modern CPUs with deep sleep states approach proportionality, but storage, memory, and network gear lag. The principle motivates consolidation (running fewer servers at higher utilisation), aggressive low-power states, and right-sizing of cloud instances. In research it underpins decisions to share rather than dedicate hardware.
References
- Barroso and Holzle 2007 IEEE Computer; ASHRAE data-centre power guidelines.
Also known as
Power proportionality · Energy-proportional computing
Machine-readable encodings
Use in your systems
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