Dependability analysis for fault-tolerant computer systems using dynamic fault graphs

Dependability analysis is an important step in designing and analyzing safety computer systems and protection systems. Introducing multi-processor and virtual machine increases the system faults´ complexity, diversity and dynamic, in particular for software-induced failures, with an impact on the overall dependability. Moreover, it is very different for safety system to operate successfully at any active phase, since there is a huge difference in failure rate between hardware-induced and softwareinduced failures. To handle these difficulties and achieve accurate dependability evaluation, consistently reflecting the construct it measures, a new formalism derived from dynamic fault graphs (DFG) is developed in this paper. DFG exploits the concept of system event as fault state sequences to represent dynamic behaviors, which allows us to execute probabilistic measures at each timestamp when change occurs. The approach automatically combines the reliability analysis with the system dynamics. In this paper, we describe how to use the proposed methodology drives to the overall system dependability analysis through the phases of modeling, structural discovery and probability analysis, which is also discussed using an example of a virtual computing system.