Three-Dimensional Redundancy Codes for Archival Storage

Abstract

Fault-tolerant disk arrays rely on replication or erasure-coding to reconstruct lost data after a disk failure. As disk capacity increases, so does the risk of encountering irrecoverable read errors that would prevent the full recovery of the lost data. We propose a three-dimensional erasure-coding technique that reduces that risk by guaranteeing full recovery in the presence of all triple and nearly all quadruple disk failures. Our solution performs better than existing solutions, such as sets of disk arrays using Reed-Solomon codes against triple failures in each individual array. Given its very high reliability, it is especially suited to the needs of very large data sets that must be preserved over long periods of time.