Developing Cost-Effective Data Rescue Schemes to Tackle Disk Failures in Data Centers

Ensuring the reliability of large-scale storage systems remains a challenge, especially when there are millions of disk drives deployed. Post-failure disk rebuild takes much longer time nowadays due to the ever-increasing disk capacity, which also increases the risk of service unavailability and even data loss. In this paper, we present a proactive data protection (PDP) framework in the ZFS file system to rescue data from disks before actual failure onset. By reducing the risk of data loss and mitigating the prolonged disk rebuilds caused by disk failures, PDP is designed to enhance the overall storage reliability. We extensively evaluate the recovery performance of ZFS with diverse configurations, and further explore disk failure prediction techniques to develop a proactive data protection mechanism in ZFS. We further compare the performance of different data protection strategies, including post-failure disk recovery, proactive disk cloning, and proactive data recovery. We propose an analytic model that uses storage utilization and contextual system information to select the best data protection strategy to achieve cost-effective and enhanced storage reliability.