Quality of storage service optimizes the use of disk storage system resources via user-defined policies and/or adaptive algorithms that manage performance and throughput, while minimizing back-end storage costs. Quality of storage service includes a variety of technologies, including cache partitioning and binding, input/output (I/O) prioritization, and the automated movement of files, logical volumes or sub-volumes, or LUNs (aka auto-tiering) between cache, solid-state drives (SSDs), high-performance and high-capacity disks and other media (such as cloud or tape), as performance needs dictate and security requirements allow.