Performability evaluation of EFT systems for SLA assurance

The performance evaluation of Electronic Funds Transfer (EFT) Systems has an enormous importance for Electronic Transactions providers, since the computing resources must be efficiently used in order to attain requirements defined in Service Level Agreements (SLA). Among such requirements, we may stress agreements on availability, reliability, scalability and security. In the EFT system, faults can cause severe degradation on system performance. The modeling of these systems, ignoring the dependability effects on performance can lead to incomplete or inaccurate results. This paper presents an expolinomial stochastic model for evaluating the performance of the EFT system processing and storage infrastructure considering load variation range. This work also presents a model for evaluating the dependability of the EFT system infrastructures and combines both models (dependability and performance) for evaluating the impact of dependability issues on the system performance. The performability analysis employs a hierarchical decomposition method aiming at reducing the computational effort and avoiding stiffness problems. Finally, a case study is presented and the respective results are depicted, stressing important aspects of dependability and performance for EFT system planning.