Providing hybrid block storage for virtual machines using object-based storage

This paper presents the design, implementation, and evaluation of a multi-tiered storage system called MOBBS, which provides hybrid block storage for Virtual Machines (VMs) on top of object-based storage infrastructure. MOBBS is mainly motivated by the gap between the lack of studies on hybrid block storage for VMs and the increasing prevalence of hybrid storage systems. By stripping disk images into partitions and intelligently storing them on different storage tiers according to real-time workload patterns, MOBBS achieves efficient use of multiple storage devices and relieves the burden of data placement. Leveraging the benefits of object-based storage, MOBBS is able to dynamically perform non-disruptive and fine-grained data migration between storage tiers and distribute the complexity of data migration across entire storage nodes. Such designs enable our system to deliver storage for VMs with high scalability and availability under an efficient use of SSDs. We evaluated a Ceph implementation of MOBBS using both block and file system workloads. The results comprehensively demonstrate MOBBS's effectiveness in performance improvement as well as efficient utilization of different storage devices.