Lifetime and QoS-aware energy-saving buffering schemes

The heterogeneous drive (HDrive), which combines solid-state disk (SSD) and HDD, brings opportunity for energy-saving and has received extensive attention recently. This paper focuses on the file buffering schemes and adaptive disk power management (DPM) scheme for HDrive. As for the first issue, we propose a frequency–energy based replacement (FEBR) scheme based on an energy-cost model; as for the second issue, we present a sliding-window based adaptive DPM scheme by taking the HDD's lifetime into account. To make the trade-off among performance, HDD's lifetime and energy-saving, we contrive a QoS-aware DPM scheme. With extensive experiments on four real-world traces, we have evaluated the effectiveness of existing replacement schemes on energy-efficiency, performance, and HDD's lifetime and compare with our proposed schemes. The experimental results have demonstrated that energy-saving in HDrive is feasible and can reach as high as 60–80%, and that FBR and its variant FEBR, and GDS are the best ones among all those online schemes evaluated while FEBR has some advantage over FBR and GDS on the whole. The results have also revealed that our proposed adaptive sliding-window-based DPM scheme can effectively control the disk's lifetime and the QoS-aware DPM scheme works well in making tradeoffs among performance, HDD's lifetime and energy-saving.

► Comprehensive comparisons are made on various energy saving replacement schemes for heterogeneous drive.
► Based on the energy-cost model, an improved scheme called frequency–energy based replacement (FEBR) is proposed.
► To ensure HDD's lifetime, an adaptive sliding-window based disk power management mechanism is proposed.
► A QoS-aware disk power management scheme is proposed.