CSPAN: cost-effective geo-replicated storage spanning multiple cloud services

Existing cloud computing platforms leave it up to applications to deal with the complexities associated with data replication and propagation across data centers. In our work, we propose the CSPAN key-value store to instead export a unified view of storage services in several geographically distributed data centers. To minimize the cost incurred by application providers, we combine two principles. First, CSPAN spans the data centers of multiple cloud providers. Second, CSPAN judiciously trades off the lower latencies and the higher storage and data propagation costs based on an application's anticipated workload, latency goals, and consistency requirements.