Cloud Storage over Multiple Data Centers

0 Abstract The increasing popularity of cloud storage services has led many companies to migrate their data into clouds for high availability whilst saving infrastructure constructions. Within the last few years, the architectures of most major cloud storage providers have evolved from single data center to multiple data centers, across different geo-locations. This architecture help improve the availability of consumers’ data, as well as safety guarantee against disasters that can disable a whole datacenter. In this chapter we introduce the architecture evolution of typical cloud storage, and common techniques used in the design, such as replication strategies, data striping methods and consistency models. We also introduce a trend in the practice of cloud storage—cloud of clouds.