DWC2: A dynamic weight-based cooperative caching scheme for object-based storage cluster

Object-based storage is emerging as a next generation of distributed storage technology. Aiming at improving the performance and load-balancing of large-scale object-based storage system, we present a dynamic weight-based cooperative caching scheme referred to as DWC², which allows an object-based storage device (OSD) to use the available free cache of the neighbouring OSD. Our proposed DWC² replaces objects based on their weights which is a function of object size, popularity and replica number, and dynamically partitions the memory of OSD into local cache and remote cache according to activity workload. An object data is cached in local cache or remote cache of the cooperative OSDs, thus increasing cache hit ratio, reducing expensive disk access time as well as improving load balance. We benchmarked our proposed DWC² with existing cooperative caching schemes under various OSD environments. Our rigorous experiment results conclusively demonstrate that our DWC² is scalable and can achieve a significant cache hit ratio, average response time, and load balancing for large-scale OSD cluster.