designing fault tolerance strategy by iterative redundancy for component-based distributed computing systems

Reliability is a critical issue for component-based distributed computing systems, some distributed software allows the existence of large numbers of potentially faulty components on an open network. Faults are inevitable in this large-scale, complex, distributed components setting, which may include a lot of untrustworthy parts. How to provide highly reliable component-based distributed systems is a challenging problem and a critical research. Generally, redundancy and replication are utilized to realize the goal of fault tolerance. In this paper, we propose a CFI (critical fault iterative) redundancy technique, by which the efficiency can be guaranteed to make use of resources (e.g., computation and storage) and to create fault-tolerance applications. When operating in an environment with unknown components’ reliability, CFI redundancy is more efficient and adaptive than other techniques (e.g., K-Modular Redundancy and N-Version Programming). In the CFI strategy of redundancy, the function invocation relationships and invocation frequencies are employed to rank the functions’ importance and identify the most vulnerable function implemented via functionally equivalent components. A tradeoff has to be made between efficiency and reliability. In this paper, a formal theoretical analysis and an experimental analysis are presented. Compared with the existing methods, the reliability of components-based distributed system can be greatly improved by tolerating a small part of significant components.