DOBBS: A Highly Available Distributed Block Storage Service for Virtual Machines

The information technology industry has seen the rapid development of storage devices, Solid State Drives (SSD), due to its high performance and low energy consumption, it has been widely used in the cloud storage systems. However, because of its high price and limited capacity, whether SSD is able to replace the Hard Disk Drives (HDD) completely is not clear. Therefore, a primary research task to be addressed is how to use SSD to provide high-performance storage systems that cost less. This paper presents a distributed software defined hybrid storage system called DOBBS which leverages the data characteristic to magnify the advantages of SSD/HDD and provide high performance block storage for virtual machines. By monitoring I/O access at runtime, DOBBS dynamically migrates data to proper storage devices for optimal performance. An efficient heat diffusion method is utilized to reach state of Global Heat Balancing. For rapid fault recovering, DOBBS also employs consensus protocol to share metadata among control nodes of cluster. DOBBS is evaluated based on several benchmarks to demonstrate its efficiency and effectiveness.