Power-aware Proactive Storage-tiering Management for High-speed Tiered-storage Systems

Large-scale high-speed mass-storage systems account for a large part of the energy consumed at data centers. To conserve energy consumed by these storage systems, we propose a high-speed tiered-storage system with a poweraware proactive method of storage-tiering management that minimizes loss of performance, which we have called the energy-efficient High-speed Tiered-Storage system (eHiTS). eHiTS consists of a tiered-storage system with high-speed online storage as the first tier and low-power nearline storage with high capacity as the second tier. All files are always stored in nearline storage when it is created, in which the hard disk drives are usually left powered off. Based on hints from a high-performance computing (HPC) application, only the volume that includes the accessed files (datasets) is copied from nearline to online storage before access. The results obtained from our testbed with 64-TB capacity revealed that eHiTS was able to conserve up to 16% of the energy consumed by an ordinary tiered-storage system with the same capacity. This corresponded to a 55%-energy saving in 1-PB capacity.