Rotated Logging Storage Architectures for Data Centers: Models and Optimizations

Abstract

We propose Ro tated Lo gging (RoLo), a new logging architecture for parallel disk-based mirrored storage systems for enhanced energy efficiency, which is one of the key concerns in modern data centers. By spreading destaging I/O activities among short idle time slots and proactively reclaiming the stale logging space, RoLo rotates loggers among a logical logging space pool formed collectively from the free storage space available among mirrored disks. We develop three flavors of RoLo, that is, RoLo-P/R/E, to emphasize performance, reliability, and energy efficiency respectively. Without the extra dedicated log disks and the corresponding centralized destaging, RoLo eliminates the additional hardware and energy costs, potential single point of failure and performance bottleneck. Furthermore, RoLo-P/R/E, applied to specific scenes correctly, can prolong the lifecycle of the disks and improve the system's energy efficiency by reducing the disk spin up/down frequency. We propose RoLo-S to further alleviate the performance bottleneck and energy consumption caused by frequent disk head seeks in on-duty logger disks. We have implemented RoLo and RoLo-S on real disk systems. Extensive trace-driven evaluations demonstrate the advantages of the three RoLo schemes over both a RAID10 system with centralized logging architecture and a typical RAID10 system, and the advantages of RoLo-S over RoLo.