UC Santa Cruz

Sensor nodes that store their data locally are increasingly being deployed in hostile and remote environments such as active volcanoes and battlefields. Observations gathered in these environments are often irreplaceable, and must be protected from loss due to node failures. Nodes may fail individually due to power depletion or hardware/software problems, or they may suffer correlated failures from localized destructive events such as fire or rockfall. While many file systems can guard against these events, they do not consider energy usage in their approach to redundancy. We examine tradeoffs between energy and reliability in three contexts: choice of redundancy technique, choice of redundancy nodes, and frequency of verifying correctness of remotely-stored data. By matching the choice of reliability techniques to the failure characteristics of sensor networks in hostile and inaccessible environments, we can build systems that use less energy while providing higher system reliability.