Energy-Saving Techniques for Disk Storage Systems
Enterprise applications and large-scale scientiﬁc computing research are generating and exploring information contents of extremely large datasets most of which are maintained online for easy accessibility. These large datasets are analyzed by a large community of researchers and must be retained and managed on thousands of traditional rotating disks and sometimes supported by mass storage systems when the data is to be migrated to deep archive. As prices of disks are getting cheaper in terms of dollars per gigabyte, the prediction is that the energy costs for operating and cooling these rotating disks will eventually outstrip the cost of the disks and the associated hardware needed to control them. Currently it is estimated that disk storage systems consume about 25%–35% of the total power used in data centers. This percentage of power consumption by disk storage systems will only continue to increase, as data-intensive applications demand fast and reliable access to online data resources. This in turn requires the deployment of power hungry faster (high rpm) and larger capacity disks. As a result, there are now many research programs in industry, government, and academia, which address reducing storage energy costs at data centers. Examples of such initiatives and programs for energy-eﬃcient computing currently underway include:
• Green Grid Consortium that include such companies as IBM, Microsoft, Google, NetApp, EMC2, etc.