A Survey of Stability Results for Redundancy Systems

Abstract

Redundancy mechanisms consist in sending several copies of a same job to a subset of servers. It constitutes one of the most promising ways to exploit diversity in multi-servers applications. However, its pros and cons are still not sufficiently understood in the context of realistic models with generic statistical properties of service-times distributions and correlation structures of copies. We aim at giving a survey of recent results concerning the stability - arguably the first benchmark of performance - of systems with cancel-on-completion redundancy. We also point out open questions and conjectures.