Parity Lost and Parity Regained

This paper has presented a formal approach to analyzing the design of data protection strategies. Whereas earlier designs were simple to verify by inspection (e.g., a parity disk successfully adds protection against full-disk failure), modern systems employ a host of techniques, and their interactions are subtle. With this approach, the paper has shown that a variety of approaches found in past and current systems are successful at detecting a variety of problems but that some interesting corner-case scenarios can lead to data loss or corruption.