Evaluation and Comparisons of Dependable Distributed Storage Designs for Clouds

Many research and development efforts have been devoted towards the design of dependable storage systems, but the effort in evaluating and comparing different designs for widely distributed environment is limited. In this paper, we develop models to evaluate the availability, security, and access performance of various storage designs for the cloud environment where storage resources are offered by multiple providers and spread over geographically distributed areas. The evaluation results show that each scheme exhibits some strengths and weaknesses. However, among various schemes, the short secret sharing approach (erasure coding combined with secret sharing the encryption keys) is most suitable for cloud storage. Our analysis methods can be applied to new storage designs and the results can be used to guide the storage system design process.