Reliability and Utilization Evaluation of a Cloud Computing System Allowing Partial Failures

Maintaining high reliability and device utilization in a cloud computing system (CCS) is crucial to any cloud service provider who will face high penalties and lose revenues if they fail to be good at both. This study proposes that allowing device partial failure in a CCS for graceful service degrading would help to obtain higher system reliability and device utilization without purchasing extra resource for the system. A model is created to represent such a multi-state system composed of multi-state devices. The system model is evaluated with Non-sequential Monte Carlo Simulation (MCS) on its reliability and device utilization. The preliminary results positively suggest that introducing and adding device multi-state increases the CCS reliability against device failures during simulation. Also, for the less reliable devices, like HDD, the results recommended a higher multi-state to compensate for their vulnerability and negative effect on system performance. A utilization index along all device dimensions is proposed in this research for a wise decision about maintaining a well-balanced and high utilized system at a lower cost.