The Role of Reliability, Availability and Serviceability (RAS) Models in the Design and Evaluation of Self-Healing Systems

In an idealized scenario, self-healing systems predict, prevent or diagnose problems and take the appropriate actions to mitigate their impact with minimal human intervention. To determine how close we are to reaching this goal we require analytical techniques and practical approaches that allow us to quantify the effectiveness of a system's remediations mechanisms. In this paper we apply analytical techniques based on Reliability, Availability and Serviceability (RAS) models to evaluate individual remediation mechanisms of select system components and their combined effects on the system. We demonstrate the applicability of RAS-models to the evaluation of self-healing systems by using them to analyze various styles of remediations (reactive, preventative etc.), quantify the impact of imperfect remediations, identify sub-optimal (less effective) remediations and quantify the combined effects of all the activated remediations on the system as a whole