Workflow management with service quality guarantees

ABSTRACT

Workflow management systems (WFMS) that are geared for the orchestration of business processes across multiple organizations are complex distributed systems: they consist of multiple workflow engines, application servers, and communication middleware servers such as ORBs, where each of these server types can be replicated on multiple computers for scalability and availability.Finding an appropriate system configuration with guaranteed application-specific quality of service in terms of throughput, response time, and tolerable downtime is a major challenge for human system administrators. This paper presents a tool that largely automates the task of configuring a distributed WFMS. Based on a suite of mathematical models, the tool derives the necessary degrees of replication for the various server types in order to meet specified goals for performance and availability as well as "performability" when service is degraded due to outages of individual servers. The paper describes the configuration tool, with emphasis on how to capture the load behavior of workflows in a realistic manner. We also present extensive experiments that evaluate the accuracy of the tool's underlying models and demonstrate the practical feasibility of automating the task of configuring a distributed WFMS. The experiments use a detailed simulation which in turn has been validated through measurements with the Mentor-lite prototype system.

REFERENCES

• 1: G. Alonso, D. Agrawal, A. El Abbadi, C. Mohan, Functionality and Limitations of Current Workflow Management Systems, IEEE Expert, 12(5), 1997
• 2: Thomas Bauer , Peter Dadam, A Distributed Execution Environment for Large-Scale Workflow Management Systems with Subnets and Server Migration, Proceedings of the Second IFCIS International Conference on Cooperative Information Systems, p.99-108, June 24-27, 1997
• 3: T Bauer, P. Dadam, Distribution Models for Workflow Management Systems - Classification and Simulation (in German), Informatik Forschung und Entwicklung, 14(4), Springer, 1999
• 4: Mesquite Software Homepage, http://www.mesquite.com
• 5: Data Engineering Bulletin Special Issue on Infrastructure for Advanced E-Services, 24(1), 2001
• 6: Asuman Dogac , T. Ozsu , L. Kalinichenko, Workflow Management Systems and Interoperability, Springer-Verlag New York, Inc., Secaucus, NJ, 2001
• 7: Michael Gillmann , Ralf Mindermann , Gerhard Weikum, Benchmarking and Configuration of Workflow Management Systems, Proceedings of the 7th International Conference on Cooperative Information Systems, p.186-197, September 06-08, 2000
• 8: Michael Gillmann , Jeanine Weißenfels , Gerhard Weikum , Achim Kraiss, Performance and Availability Assessment for the Configuration of Distributed Workflow Management Systems, Proceedings of the 7th International Conference on Extending Database Technology: Advances in Database Technology, p.183-201, March 27-31, 2000
• 9: Claus Hagen , Gustavo Alonso, Highly Available Process Support Systems: Implementing Backup Mechanisms, Proceedings of the 18th IEEE Symposium on Reliable Distributed Systems, p.112, October 18-21, 1999
• 10: David Harel , Eran Gery, Executable Object Modeling with Statecharts, Computer, v.30 n.7, p.31-42, July 1997 [doi>10.1109/2.596624]
• 11: Performance Evaluation: Origins and Directions, January 2000
• 12: IONA Technologies PLC, User Manuals of Orbix 2.3, 1997
• 13: Justus Klingemann , Jürgen Wäsch , Karl Aberer, Deriving Service Models in Cross-Organizational Workflows, Proceedings of the Ninth International Workshop on Research Issues on Data Engineering: Information Technology for Virtual Enterprises, p.100, March 23-24, 1999
• 14: Mohan Kamath , Gustavo Alonso , Roger Günthör , C. Mohan, Providing High Availability in Very Large Worklflow Management Systems, Proceedings of the 5th International Conference on Extending Database Technology: Advances in Database Technology, p.427-442, March 25-29, 1996
• 15: A. Lazcano, G. Alonso, H. Schuldt, C. Schuler, The WISE approach to Electronic Commerce, Int'l. Journal of Computer Systems Science & Engineering, 15(5), 2000
• 16: F. Leymann, D. Roller, Production Workflow, Prentice Hall, 1999
• 17: P. Mills, C. Loosley, A Performance Analysis of 40 e-Business Web Sites, White Paper, Keynote Systems Inc., 2001
• 18: Herb Schwetman, Model-based systems analysis using CSIM18, Proceedings of the 30th conference on Winter simulation, p.309-314, December 13-16, 1998, Washington, D.C., United States
• 19: German Shegalov , Michael Gillmann , Gerhard Weikum, XML-enabled workflow management for e-services across heterogeneous platforms, The VLDB Journal — The International Journal on Very Large Data Bases, v.10 n.1, p.91-103, August 2001
• 20: Hans Schuster , Jens Neeb , Ralf Schamburger, A configuration management approach for large workflow management systems, Proceedings of the international joint conference on Work activities coordination and collaboration, p.177-186, February 22-25, 1999, San Francisco, California, United States
• 21: Robin A. Sahner , Kishor S. Trivedi , Antonio Puliafito, Performance and reliability analysis of computer systems: an example-based approach using the SHARPE software package, Kluwer Academic Publishers, Norwell, MA, 1996
• 22: H. C. Tijms, Stochastic Models, John Wiley and Sons, 1994
• 23: Transaction Processing Performance Council, http://www.tpc.org
• 24: J. Weissenfels, M. Gillmann, O. Roth, G. Shegalov, W. Wonner, The Mentor-lite Prototype: A Light-Weight Workflow Management System, ICDE, California, 2000

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.4 INFORMATION SYSTEMS APPLICATIONS
      H.4.1 Office Automation
          Subjects: Workflow management

Additional Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.4 Distributed Systems
          Subjects: Client/server

  H. Information Systems
  H.3 INFORMATION STORAGE AND RETRIEVAL
      H.3.4 Systems and Software
          Subjects: Distributed systems
  H.4 INFORMATION SYSTEMS APPLICATIONS
      H.4.1 Office Automation
          Subjects: Groupware

General Terms:
Algorithms, Documentation, Theory