DifferStore: A differentiated storage service in object-based storage system

This paper presents a differentiated storage service in object-based storage system, called DifferStore. To enable differentiated storage service for different applications in a single object-based storage platform, DifferStore utilizes a two-layer architecture to efficiently decouple upper-layer application specific storage policies and lower-layer application independent storage functions. For the lower application independent layer, this paper proposes a weight-based object I/O scheduler with differentiated scheduling policy for different request classes, and a versatile storage manager. The versatile storage manager implements differentiated storage policies in terms of disk layout and free space allocation, as well as an efficient object namespace management enabling directly access object on-disk data just with object ID. The DifferStore also provides ability for upper application specific layer to assign complex striping, placement, load-balancing policies and specific metadata structure of file. Experimental evaluation on our user space prototype demonstrates that the DifferStore can perform well under mixed workloads and satisfy requirements of different applications.