Cloud-of-clouds Storage Made Efficient: A Pipeline-based Approach

Cloud-of-clouds storage is a recent approach to improve the security and reliability of data storage for online applications. It encrypts and encodes the user data, and disperses the results to multiple clouds. Thus, the data can tolerate cloud failures, while cannot be inferred even when some clouds are compromised. However, efficiency is a well-known challenge to such a paradigm, since its data storing process (also known as the dispersal process) is time-consuming involving encryptions, encoding, and transmissions, posing a barrier to its wide application. How to speed up the dispersal process is yet to be well addressed. We observe that the dispersal process consists of two types of operations: calculation and transmission. We find that they can execute simultaneously. Hence, the process can be optimized with a pipelined architecture. To this end, we propose the pipelined versions of two state-of-the-art cloud-of-clouds storage approaches, i.e., AONT-RS and CAONT-RS. We implement both proposals and release them open-source online. To verify their effectiveness, extensive experiments are conducted on a prototype storage system with real-world traces. The results show that the pipelined architecture can improve the performance of the dispersal process.