Requirements real-time aggregate dispersed data access hot set scale refs [1,2,5,6,12,14,34,36] Front-end cluster read heavy workload (100:1 R/W) wide fanout handle failures 10 Mops/s Q: what is a wide fanout Multiple FE clusters single geo region control data replication data consistency 100 Mops/s Multiple regions muliple geo regions storage replication data consistency 1 Bops/s Pre-memcached High fanout data dependency graph for a small user request Look-aside cache why deletes over set