A Queuing Model for Business Processes Elasticity Evaluation

Cloud Computing is a recent trend in information technology, it refers to a model for enabling ubiquitous, convenient, on demand network access to a shared pool of computing resources that can be rapidly provisioned and released with minimal effort. One of the characteristics of the Cloud is elasticity. Elasticity is the ability of Cloud service to rapidly change the amount of its allocated resources in order to meet the demands variation while ensuring a given QoS. Cloud environments are being increasingly used for deploying and executing business processes and particularly Service-based Business Processes (SBPs). Provisioning of elastic infrastruc-tures and platforms is not sufficient to provide elasticity of SBPs. Therefore, SBPs must be provided with elasticity so that they will be able to be adapted to the variations of workload, while ensuring their functional and non-functional properties. In this paper, we are interested in evaluating SBP selasticity. To do that, we propose to model SBPs elasticity using queuing model system with variable number of services copies to represent SBPs adaptation to demands variation. Afterwards, we propose to use this queuing model to evaluate SBPs elasticity.