Understanding Data Survivability in Archival Storage Systems
Preserving data for a long period of time in the face of faults, large and small, is crucial for designing reliable archival storage systems. However, the survivability of data is different from the reliability of storage because typically, data are stored in more than one storage at a given moment. Previous studies of reliability ignore the former. The authors present a framework for relating data survivability and storage reliability, and use the framework to gauge the impact of rare but large-scale events on data survivability. They also present a method to track all copies of data and the condition of all the online and offline media, devices and systems on which they are stored uninterruptedly over the whole lifetime of the data.