@phdthesis{Gr12, author = {Gradl, Stephan}, title = {Performance-Modellierung und Simulation eines SAP-ERP-Systems}, year = {2012}, school = {Technische Univesit{\"{a}}t M{\"{u}}nchen}, address = {M{\"{u}}nchen}, type = {Dissertation}, } @inproceedings{MaGrScWiKr11, author = {Mayer, Manuel and Gradl, Stephan and Schreiber, Veronika and Wittges, Holger and Krcmar, Helmut}, title = {A Survey on Performance Modelling and Simulation of SAP Enterprise Resource Planning Systems}, booktitle = {10th International Conference on Modeling and Applied Simulation}, publisher = {Diptem Universita di Genoa}, pages = {347-352}, year = {2011}, location = {Rom, Italy}, abstract = {IT industry faces the need of a robust, reliable and scalable architecture to support enterprise-scale IT systems. One of such complex systems are enterprise resource planning (ERP) systems. ERP systems support company-wide processes and are considered as a critical success factor for a reliable business operation. Despite the importance of performance prediction of IT systems shown in literature, there is not much work done in the context of ERP systems. This paper presents the results of an online survey conducted in December 2010. 36 IT decision makers of various industries and company sizes took part in this survey, which contained questions about whether and to which degree performance modelling and simulation is currently implemented in companies, which tools are used to measure the performance of ERP systems, and which requirements are expected.}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1981/}, } @inproceedings{GrMaDaEsWiKr11, author = {Gradl, Stephan and Mayer, Manuel and Danciu, Alexandru and Escrihuela, Ramon and Wittges, Holger and Krcmar, Helmut}, title = {Measuring the Buffer Occupation of SAP ERP System Applications}, booktitle = {13th International Conference on Enterprise Information Systems}, publisher = {SciTePress}, pages = {266-272}, year = {2011}, location = {Beijing, China}, abstract = {Enterprise resource planning (ERP) systems form the backbone for the execution, controlling and management of business processes in today's large companies. Availability and performance of ERP systems is extraordinary critical for a company as even short unavailability or reduced throughput can be very costly. As companies are evolving, the number of applications and the kinds of applications that have to be supported are rising, which inherently also increases performance needs. However, the determination of what makes up the performance needs is critical. The performance of SAP ERP systems strongly depends on the usage of buffers for caching database contents. In order to predict the performance of SAP ERP systems, it is necessary to understand and measure the buffer usage of applications running on SAP ERP systems. In this work we explain the basic concepts and introduce a method for measuring the buffer usage of SAP ERP applications. This method will be illustrated by a case study where each step of a business process, executed on a SAP ERP system, will be analyzed according to the memory usage}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1985/}, crossref = {DBLP:conf/iceis/2011-3 <#DBLP:conf/iceis/2011-3>}, } @inproceedings{GrMaDaWiKr11, author = {Gradl, Stephan and Mayer, Manuel and Danciu, Alexandru and Wittges, Holger and Krcmar, Helmut}, title = {Understanding the Performance Behavior of a SAP ERP System for the Use of Queuing Models}, booktitle = {10th International Conference on Modeling and Applied Simulation}, publisher = {Universita di Genova, Genoa}, pages = {361-370}, year = {2011}, abstract = {ERP systems support the management of a company's resources. As a large number of business-relevant processes are supported by ERP systems, the performance and availability of those systems is crucial for the success of a company (Apache Software Foundation 2010). We analyze the response time of 49350 requests. Furthermore, we interpret the system's internal behavior by fetching and analyzing the statistical data. As results we can show that queuing models can be used for evaluating the performance of SAP ERP systems as the response time behavior follows the assumptions of queuing theory, resulting in nearly constant resource consumption per user interaction task, independent of the number of parallel requests. By analyzing the reasons for these results, important insights into the performance behavior of SAP ERP systems for performance analysis and prediction are achieved.}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1986/}, } @inproceedings{GrMaWiKr10, author = {Gradl, Stephan and Mayer, Manuel and Wittges, Holger and Krcmar, Helmut}, title = {Modeling ERP Business Processes Using Layered Queueing Networks}, booktitle = {12th International Conference on Enterprise Information Systems}, publisher = {INSTICC}, pages = {255-260}, year = {2010}, location = {Funchal, Portugal}, abstract = {This paper presents an approach how to simulate enterprise resource planning systems (ERP) using Layered Queueing Networks (LQN). A case study of an existing production planning process shows how LQN models can be exploited as a performance analysis tool. To gather data about the internal ERP system's architecture, an internal trace is analyzed and a detailed model is built to evaluate system?s performance and scalability in terms of response times with an increasing number of users and CPUs. It is shown, that the solving results match the characteristics in practice. Depending on the number of CPUs, constant response times are observed up to a certain number of concurrent users.}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1605/}, crossref = {DBLP:conf/iceis/2010-3 <#DBLP:conf/iceis/2010-3>}, } @inproceedings{TeLeGrMaKr10, author = {Tertilt, Daniel and Leimeister, Stefanie and Gradl, Stephan and Mayer, Manuel and Krcmar, Helmut}, title = {Towards an evolutionary model generation for ERP performance simulation}, booktitle = {IADIS International Conference on Intelligent Systems and Agents (ISA)}, year = {2010}, location = {Freiburg, Germany}, abstract = {The performance of ERP systems is a critical success factor for the reliable operation of a business. A promising approach to cope with the complexity of nowadays' ERP systems and to predict their actual behavior is simulation. Commercial ERP systems, however, only provide limited insight and thus several components have to be handled as black boxes and require a modeling approach. In this paper we depict an approach to increase the accuracy of ERP system performance simulation by using an evolutionary algorithm for modeling the black boxes performance behavior. We can show that evolutionary algorithms are able to generate performance models for ERP components based on measured performance data that describe the performance behavior of these components accurately. Furthermore we point out the characteristics of the algorithm, as well as its advantages and disadvantages, and give an outlook about the future research.}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1834/}, } @inproceedings{GrBoWiKr09, author = {Gradl, Stephan and B{\"{o}}gelsack, Andr{\'{e}} and Wittges, Holger and Krcmar, Helmut}, title = {Layered Queuing Networks For Simulating Enterprise Resource Planning Systems}, booktitle = {7th International Workshop on Modelling, Simulation, Verification and Validation of Enterprise Information Systems}, publisher = {INSTICC}, pages = {85-92}, year = {2009}, location = {Milano, Italy}, abstract = {As Enterprise Resource Planning systems (ERP) form the backbone of today's business processes the stability and performance of those systems is vital to the whole company. In many cases less is known what happens to the performance of an ERP system when a patch is applied or changes are made to the ERP system. This paper presents an approach how to simulate Enterprise Resource Planning systems (ERP) before changes are made to the system. The approach involves the development of so called Layered Queuing Networks (LQN). To construct such a LQN the paper utilizes a trace in the ERP system to gather data about the internal ERP system?s architecture. These data is used to construct a section of the internal architecture of the ERP system. The ERP system?s architecture is transformed into a LQN and the LQN is simulated.}, url = {http://vmkrcmar23.informatik.tu-muenchen.de/1604/}, crossref = {DBLP:conf/vveis/2009 <#DBLP:conf/vveis/2009>}, }