CPM: Cooperative power management for object-based storage cluster

Disk idle periods in server workload are short, which significantly limits the effectiveness of underline disk power management. To release this limitation, we present a cooperative power management (referred to as CPM) scheme to save energy with performance guarantee for object-based storage cluster. CPM reclaims idle memories of neighboring object-based storage devices (OSDs) over high speed network as remote cache to store evicted objects. Then requests missed in local cache could be hit by remote cache, and local disk does not necessarily spin back up to service these requests. Hence, CPM can artificially create long idle periods to provide more opportunities for underlying disk power management. CPM minimizes the risk of performance and energy penalty by spinning down disks only when predicted idle period is long enough to justify state-transition energy. Our rigorous experiment results conclusively demonstrate that CPM can dynamically adapt to workload changes and outperform existing solutions in terms of energy saving and performance for large-scale OSD cluster.