Active probing strategies for problem diagnosis in distributed systems

We address the task of problem determination in a distributed system using probes, or test transactions, which gather information about system components. Effective probing requires minimizing the cost of probing while maximizing the diagnostic accuracy of the probe set. We show that pre-planning an optimal probe set is NP-hard and present polynomial-time approximation algorithms that perform well. We then implement an active probing strategy which selects probes dynamically and show that it yields a significant reduction in probe set size in both simulation and a real system environment.