Onion and pizza: New disk partitioning schemes for virtualization systems

The traditional disk partitioning scheme commonly used in a virtualization system divides a disk into multiple partitions in a coarse-grained manner, which causes a long seek distance when multiple virtual machines run concurrently. To overcome this drawback, we propose two novel schemes, called onion and pizza. The onion scheme makes partitions in an interleaved way, which leads to not only reduce a seek distance but also enhance fairness among virtual machines. The pizza scheme goes one step further that makes partitions in a vertical fashion, not a horizontal fashion, so that requests from different virtual machines can be served in a same cylinder. In additional, new sector mapping is devised for efficiency of the two schemes. Real implementation based experiments have shown that our proposal can enhance I/O bandwidth up to 95% with an average of 25%, compared with the traditional scheme.