Buffer-Aware Data Migration Scheme for Hybrid Storage Systems

Since solid-state drives (SSD) have high read speed, they are integrated into a traditional hard disk drive (HDD)-based storage systems for improving the overall performance. The data migration, which is responsible for moving the data between the HDD and SSD so as to maximize the I/O performance, may result in the overhead in terms of unnecessary page migrations. To deal with it, we develop a novel buffer-aware data migration scheme to boost the performance for hybrid storage systems consisting of HDD and SSD by exploiting the content information in the buffer cache. It first introduces two new data states to reclassify the data, which are placed on the hybrid storage systems equipped with HDD and SSD. Then, it tries to improve the efficiency of data migration by copying the newly updated data in the buffer cache instead of the old version in the HDD or SSD into the other device. We also model the process of data migration operation and assess the effectiveness of the buffer-aware data migration scheme theoretically. Experimental results reveal that the buffer-aware data migration scheme can reduce the runtime time by up to 18% and the write count by up to 14% over the buffer-unaware data migration scheme under three benchmarks and a real workload.