Value-based tiering management on heterogeneous block-level storage system

As the scale of datacenter continues to grow, it is hard to keep servers homogenous, with the same hardware and performance characteristics. Today´s datacenters commonly operates on several generations of servers from multiple vendors, and mix both high-end and low-end devices together to deliver service quality requirement with lowest cost. However, the heterogenous environment also complicates the management of the datacenters, especially in terms of resource allocation. In this paper, we focus on the resource allocation of a tightly unified block-level storage with SSD and HDD. We conduct experiments to quantify the performance of difference access patterns on each type storage devices. Then formulate our resource allocation problem into a ILP (Integer Linear Programming), and proposed data migration algorithms based on the observations. We evaluate our solution by implementing a heterogenous storage consist of HDD, SDD and iSCSI HDD, and show the data access response time can be reduced by 27%.