Efficient Byzantine-tolerant Erasure-coded Storage (CMU-PDL-03-104)

This paper describes a decentralized consistency protocol for survivable storage that exploits local data versioning within each storage-node. Such versioning enables the protocol to efficiently provide linearizability and wait-freedom of read and write operations to erasure-coded data in asynchronous environments with Byzantine failures of clients and servers. By exploiting versioning storage-nodes, the protocol shifts most work to clients and allows highly optimistic operation: reads occur in a single round-trip unless clients observe concurrency or write failures. Measurements of a storage system prototype using this protocol show that it scales well with the number of failures tolerated, and its single request response time compares favorably with an efficient implementation of Byzantine-tolerant state machine replication.