Scaling the Performance and Cost for Elastic Cloud Web Services

Cloud computing is the latest evolution of computing where the IT resources are offered as services following the “pay-per-usage” pricing model. Cloud’s scalability feature causes variable price for resources governed by the cloud service providers. Therefore, the cloud customers’ main interest is whether the performance scales to the price for the leased resources in the cloud. In this paper we analyze the variable server load impact on the performance and the cost of two web services that utilize memory and CPU resources. In order to determine the real cost of the rented CPU resources, we experimented with different number of concurrent messages with different sizes. The results concerning the memory demanding web service show that the lowest cost is obtained when the web service is hosted on two CPUs, whereas the results concerning the web service which additionally utilizes CPU show that the lowest cost is achieved when it is hosted on one CPU and linearly rises with the resources.