The Need for Temperature-Aware Storage Systems

Storage has become ubiquitous. Disk drives are commonplace in most laptops and desktops. In addition, they are used in large numbers in high-end server systems. Storage devices has also proliferated the consumer electronics market with their use in products like cameras, and portable music devices. This widespread usage of disks has been the result of tremendous growth in both the density and speed of these devices. Over the past two decades, we have been enjoying a 40 percent annual growth in the data rate of disks, due to innovations in the recording technology coupled with a scaling up of the drive RPM. Since raising the RPM increases the heat that is generated due to viscous dissipation by nearly a cubic factor, in order to design the drives for a constant thermal envelope, the platter sizes are also shrunk, as the latter has a fifth power impact on the temperature. In this paper, it shall be shown that this thermal-constrained scaling is going to be very challenging to sustain even for very small platter sizes, causing a significant slowdown in the pace of performance growth in future drives. Using real workloads, the need for continued scaling of the data rate is motivated. Some simple techniques will be presented that can be employed to overcome these effects. Finally, it will also be shown that managing temperature in disks cannot necessarily be tackled merely via energy saving techniques