A Case Study in Eliciting Scalability Requirements

Scalability is widely recognized as an important software quality, but it is a quality that historically has lacked a consistent and systematic treatment. To address this problem, we recently presented a framework for the characterization and analysis of software systems scalability. That initial work did not provide means to instantiate the variables and functions to be used in the analysis, which could compromise its results. This risk can be mitigated through a systematic exploration of system scalability goals in the application domain during requirements engineering. This paper describes our application of goal-oriented requirements engineering (GORE) for eliciting the scalability requirements of a large, real-world financial fraud detection system. The case study reveals both the suitability and the limitations of GORE as a technique for eliciting the information needed by stakeholders to specify scalability goals of a system. In the paper, we describe these findings in detail and chart a course for future research in extending goal-oriented techniques to scalability requirements.