... Hybrid storage systems (HSS) take advantage of both fast-yet-small storage devices and large-yet-slow storage devices to deliver high storage capacity at low latency [27,39,40,55,62,70,74,76,82,84,100,115,130,184,229,230,238,244,253,258,267,270,274,283,284,287,288,291,312,343,347,349,356,396,408,409,439,441,453,456,489,511,517,518,520,530,531,540]. The key challenge in designing a high-performance and cost-effective hybrid storage system is to accurately identify the performance-criticality of application data and place data in the "best-fit" storage device [343]. ...