Modeling multi-site computation offloading in unreliable cloud environments

Abstract

Offloading heavy computations from a mobile device to cloud servers can reduce the power consumption of the mobile device and improve the response time of the mobile application. However, the gains of offloading can be significantly affected by failures of cloud servers and network links. In this paper, we propose a fault-aware, multi-site computation offloading model capable of finding a near-optimal allocation of tasks to resources. Our model minimizes the weighted sum of response time and energy consumption. It incorporates the effect of failures in response time and energy computations for various allocations. We create a fault injection framework to evaluate an allocation under various failure rates and recovery mechanisms. The experiments carried out with our fault injection framework demonstrate that for an application that needs to be offloaded to an unreliable cloud environment, our proposed fault-aware model can determine an allocation—based on the type (server or network link) of failures, failure rates, and the employed failure recovery mechanisms—that yields lower response time and lower energy consumption in comparison to a model that ignores such failures and the costs of recovery mechanisms.