Energy Efficiency Is Not Enough, Energy Proportionality Is Needed!

Due to the energy consumption/resource utilization characteristics of todays centralized DB servers, the fastest configuration is also the most energy-efficient one. Extensive use of SSDs alone cannot enable a fundamental change of this overall picture, because the storagerelated energy consumption is typically only a little fraction of the overall energy budget. Even, when this storage-related share is (almost) completely reduced by optimized flash-aware buffer management, the saving effect achieved may be limited by less than ∼10%. Therefore, we have designed a cluster of wimpy computing nodes called WattDB, where the individual nodes are dynamically attached and detached to the cluster on demand – depending on the current workload needs –, thereby aiming at energy-proportional DB management.