Minimal Replication Cost for Availability

Today, the utility of many replicated Internet services is limited by availability rather than raw performance. To better understand the effects of replica placement on availability, we propose the problem of minimal replication cost for availability. Let replication cost be the cost associated with replica deployment, dynamic replica creation and teardown at n candidate locations. Given client access patterns, replica failure patterns, network partition patterns, a required consistency level and a target level of availability, the minimal replication cost is the lower bound on a system's replication cost. Solving this problem also answers the dual question of optimal availability given a constraint on replication cost