Service Scalability Over the Cloud

Cloud Computing promises an easy way to use and access to a large pool of virtualized resources (such as hardware, development platforms and/or services) that can be dynamically provisioned to adjust to a variable workload, allowing also for optimum resource utilization. This pool of resources is typically exploited by a pay-per-use model in which guarantees are offered by means of customized SLAs. Therefore, Cloud Computing automated provisioning mechanisms can help applications to scale up and down systems in the way that performance and economical sustainability are balanced. So, what does it mean to scale?