Cost-Aware Performance Modeling of Multi-tier Web Applications in the Cloud

Typical web applications employ a multi-tier architecture. Traditionally, a pool of physical servers is used to host web applications. To handle the dynamic workloads which characterize today’s web applications, several authors have proposed schemes for dynamic resource provisioning. Such schemes add more servers during peak loads and remove servers during other times. Advances in cloud computing technologies have created new perspectives for real-time dynamic provisioning. The elastic nature of cloud computing systems allows system administrators to quickly scale resources to respond to unexpected load changes. In such systems, dynamic provisioning is not only concerned with meeting Service Level agreements, but also must take into account monetary costs. In this paper, we exploit performance modeling in the context of cloud computing (Amazon EC2). Having such performance models enables understanding the trade-off between performance and cost, a cornerstone in developing dynamic provisioning performance management schemes.