Modelling and Evaluation of Recovery Control for Degradable/Recoverable Information Systems

This paper proposes an effective design method of degradable/recoverable information system by using two methods of sate diagram matrix (SDM), which is a structural state based description formalism, and total high performance time (THPT) which is a performance-related system reliability measure. SDM is useful to identify pending states for restoring system state from a degraded state to a normal state. Control method of recovery procedure in the pending states is detailed by using extended stochastic Petri net (ESPN) to evaluate THPT. We illustrate effectiveness of combining these methods for degradable/recoverable information system behavioural specification and performance-related reliability evaluation through an application of storage system with mirrored disks