Substituting Failure Avoidance for Redundancy in Storage Fault Tolerance

The primary mechanism for overcoming faults in modern storage systems is to introduce redundancy in the form of replication and error correcting codes. The costs of such redundancy in hardware, system availability and overall complexity can be substantial, depending on the number and pattern of faults that are handled. This dissertation describes and analyzes, via simulation, a system that seeks to use disk failure avoidance to reduce the need for costly redundancy by using adaptive heuristics that anticipate such failures. While a number of predictive factors can be used, this research focuses on the three leading candidates of SMART errors, age and vintage. This approach can predict where near term disk failures are more likely to occur, enabling proactive movement/replication of at-risk data, thus maintaining data integrity and availability. This strategy can reduce costs due to redundant storage without compromising these important requirements.