Brief Announcement: Consistency and Complexity Tradeoffs for Highly-Available Multi-Cloud Store


An emerging multi-cloud storage paradigm suggests replicating data across multiple cloud storage services, potentially operated by distinct providers. In this paper, we study the impact of the storage interfaces and consistency semantics exposed by individual clouds on the complexity of the reliable multi-cloud storage implementation. Our results establish several inherent space and time tradeoffs associated with emulating reliable objects over a collection of unreliable storage services with varied interfaces and consistency guarantees.