Improving the Performance of Heterogeneous Data Centers through Redundancy

We analyze the performance of redundancy in a multi-type job and multi-type server system where PS is implemented. We characterize the stability condition, which coincides with that of a system where each job type only dispatches copies into its least-loaded servers, and those copies need to be fully served. We then investigate the impact of redundancy in the stability condition by comparing that to the stability condition of a non-redundant system in which a job arrival is routed to only one randomly selected compatible server. We observe that if server loads are sufficiently heterogeneous redundancy can considerably improve the stability region of the system.