Abstract: Cloud data centers are increasingly becoming the first choice for many Internet enterprises,especially the newly formed and small ones,because it is convenient to deploy the applications,easy to maintain them,and unnecessary to build a private in-house infrastructure.In the cloud environments based on infrastructure as a service,Internet companies can rent the cloud infrastructure dynamically in accordance with the service requirements.In this way,they have the chance to save the costs of renting infrastructure with the performance guarantees.However,the existing methods for balancing workloads and scaling resources in the industry practice are only able to monitor the states of virtual machines,not the custom performance metrics such as the number of live application sessions.So these scaling methods cannot decide the exact resource demands according to the service requirements.In addition,there are few academic studies on reducing the renting costs and employing the billing resources efficiently in the cloud environment.On the basis of these points,this paper proposed a cost-efficient resource management approach for the cloud multi-tier applications,aiming to save infrastructure costs and improve the application performance with the billing resources.Last,we compared the proposed method with the algorithms used in practice by simulating them with the ripe benchmarks.The results indicate that our method can not only improve the quality and performance of the application,but also reduce the cost of renting infrastructure largely.

Key words: Cloud computing,Cost-efficient,Multi-tier architecture,Resource scaling,Workload balance