Patrick Eaton

OceanStore: an architecture for global-scale persistent storage

OceanStore is a utility infrastructure designed to span the globe and provide continuous access to persistent information. Since this infrastructure is comprised of untrusted servers, data is protected through redundancy and cryptographic techniques. To improve performance, data is allowed to be cached anywhere, anytime. Additionally, monitoring of usage patterns allows adaptation to regional outages and denial of service attacks; monitoring also enhances performance through pro-active movement of data. A prototype implementation is currently under development.

Maintenance-free global data storage

Explores mechanisms for storage-level management in OceanStore, a global-scale distributed storage utility infrastructure, designed to scale to billions of users and exabytes of data. OceanStore automatically recovers from server and network failures, incorporates new resources and adjusts to usage patterns. It provides its storage platform through adaptation, fault tolerance and repair. The only role of human administrators in the system is to physically attach or remove server hardware. Of course, an open question is how to scale a research prototype in such a way to demonstrate the basic thesis of this article - that OceanStore is self-maintaining. The allure of connecting millions or billions of components together is the hope that aggregate systems can provide scalability and predictable behavior under a wide variety of failures. The OceanStore architecture is a step towards this goal.

Antiquity: exploiting a secure log for wide-area distributed storage

Antiquity is a wide-area distributed storage system designed to provide a simple storage service for applications like file systems and back-up. The design assumes that all servers eventually fail and attempts to maintain data despite those failures. Antiquity uses a secure log to maintain data integrity, replicates each log on multiple servers for durability, and uses dynamic Byzantine fault-tolerant quorum protocols to ensure consistency among replicas. We present Antiquitys design and an experimental evaluation with global and local testbeds. Antiquity has been running for over two months on 400+ PlanetLab servers storing nearly 20,000 logs totaling more than 84 GB of data. Despite constant server churn, all logs remain durable.

Efficiently binding data to owners in distributed content-addressable storage systems

Distributed content-addressable storage systems use self-verifying data to protect data integrity and to enable graceful scaling. One feature commonly missing from these systems, however, is the ability to identify the owner of a piece of data in a non-repudiable manner. While a solution that associates a certificate with each block of data is conceptually simple, researchers have traditionally claimed that the cost of creating and maintaining certificates is too great. In this paper, we demonstrate that systems can, in fact, efficiently map data to its owner in a secure and non-repudiable fashion. To reduce the cost of creating and maintaining certificates, we extend the traditional content-addressable interface to allow the aggregation of many small data blocks into larger containers. The aggregation is performed in a way that also supports self-verifying data at the granularity of the block and container, fine-granularity access, and incremental updates. We describe two prototype implementations and present preliminary performance results from deployments on PlanetLab and a local cluster

Improving bandwidth efficiency of peer-to-peer storage

We broaden the applicability of peer-to-peer storage infrastructures to weakly-connected clients. We present a client-side technique that exploits the commonality between consecutive versions of a file to reduce the bandwidth required to store and retrieve files in a peer-to-peer storage infrastructure. We then present a novel data structure that allows us to use this technique in an environment where peers cannot be trusted to perform operations over unencrypted data. We have implemented the technique in the OceanStore prototype. Additionally, with simulations, we have demonstrated that the technique can reduce client-perceived latency of write and read operations by up to 80% compared to techniques used in current systems.

Improving bandwidth ef .ciency of peer-to-peer storage

We broaden the applicability of peer-to-peer storage infrastructures to weakly-connected clients. We present a client-side technique that exploits the commonality between consecutive versions of a file to reduce the bandwidth required to store and retrieve files in a peer-to-peer storage infrastructure. We then present a novel data structure that allows us to use this technique in an environment where peers cannot be trusted to perform operations over unencrypted data. We have implemented the technique in the OceanStore prototype. Additionally, with simulations, we have demonstrated that the technique can reduce client-perceived latency of write and read operations by up to 80% compared to techniques used in current systems.