A Novel Cost-Effective Disk Scrubbing Scheme

Junping Liu, Ke Zhou, Liping Pang, Zhikun Wang, Yuhui Deng, Dan Feng

Abstract: A distinct benefit of disk scanning or scrubbing operation is identifying the potential failure sectors as early as possible, thus providing high reliability. Obviously, the higher the scrubbing frequency is, the higher the system reliability is. However, it may take a few hours for a scanning process to check the whole disk. In other words, the scrubbing process may result in a downtime or a lower system performance. Furthermore, the scrubbing process consumes energy. In order to reduce the impact of disk scrubbing on disk performance and energy consumption, system designers choose to scan the disk in a low frequency, which results in a lower reliability. Additionally, conventional disk scrubbing schemes assume that the disk failure rate is constant, while the recent researches show the disk failure rate is more complex. In this paper, we present a novel scrubbing scheme to solve the above challenges. In the scheme, an optimum scrubbing cycle is decided by keeping a balance between data loss cost, scrubbing cost, and disk failure rate. Our research shows that the scrubbing scheme is applicable for storage with low-capacity disk and inexpensive data.