w-TG: A Combined Algorithm to Optimize the Runtime of the Grid-Based Workflow Within an SLA Context

In the Grid Computing environment, many users need the results of their calculations within a specific period of time. Examples of those users are weather forecasters running weather forecasting workflows, and automobile producers running dynamic fluid simulation workflow Lovas et al. (2004). Those users are willing to pay for getting their work completed on time. However, this requirement must be agreed on by both, the users and the Grid provider, before the application is executed. This agreement is contained in the Service Level Agreement (SLA) Sahai et al. (2003). In general, SLAs are defined as an explicit statement of expectations and obligations in a business relationship between service providers and customers. SLAs specify the a-priori negotiated resource requirements, the quality of service (QoS), and costs. The application of such an SLA represents a legally binding contract. This is a mandatory prerequisite for the Next Generation Grids.