Realistic system states and representative workloads are required to evaluate a hierarchical storage management (HSM) system. The existing method to evaluate a HSM system reconstructs system states by replaying a trace within period of time. Ignoring files not used recently, the result of this method is not convincing enough. This paper proposes DMStone, a tool for evaluating HSM systems. DMStone uses file-system snapshots to generate a system state. Furthermore, it extracts workload characteristics by comparing two contiguous snapshots and generates representative workloads. DMStone can provide a realistic file-system state, including files used recently and those not used for a long time. Moreover, it makes subsequent workloads conform to realistic system states.