Performance and power consumption are two important design objectives for data centers consisting of thousands or tens of thousands of disks (or disk arrays).To leverage the two objectives,in this study we propose a multi-version disk array (MDA).The main idea of MDA is to exploit the I/O workload characteristics to guide the replication strategy by replicating multiple versions of the popular data blocks and simply offloading the write data to the free space of the reserved version region,thus achieving high performance in the burst period and low power consumption in the idle period.Our prototype implementation of MDA and the performance evaluations show that the performance of MDA outperforms that of traditional RAID10 by up to 34.4% and 42.3% in terms of the average response time for the online transaction processing (OLTP) application I/O and search engine I/O,respectively.Moreover,the energy efficiency of MDA outperforms that of RAID10 by up to 48.7% and 36.4%,respective to the aforementioned measures.
