Workflow management systems (WFMS) are a cornerstone of mission-criticial, possibly cross-organizational business processes. For largescale applications both their performance and availability are crucial factors, and the system needs to be properly configured to meet the application demands. Despite ample work on scalable system architectures for workflow management, the literature has neglected the important issues of how to systematically measure the performance of a given system configuration and how to determine viable configurations without resorting to expensive trial-anderror or guesswork. This paper proposes a synthetic benchmark for workflow management systems; based on the TPC-C order-entry benchmark, a complete e-commerce workflow is specified in a system-independent form. This workflow benchmark, which stresses all major components of a workflow system and is parameterized in a flexible manner, has been applied to two operational systems, the commercial system Staffware97 and our own prototype system Mentor-lite. The paper reports performance results from our measurements and discusses lessons learned. In particular, the results demonstrate the scalability of the Mentor-lite architecture. The measurements also underline the need for configuring systems intelligently, and the paper outlines an auto-configuration tool that we have been building to this end. 1 Introduction 1.1 Problem Statement Workflow technology has penetrated into mission-critical, enterprise-wide or even crossorganizational, business applications. Typical examples are insurance claim processing, cargo shipping, or healt-care tracking and planning, and workflow technology is also embedded in many e-commerce services. Following the terminology of WfMC [32] (see also [5, 6, 8, 15, 18]), a workflow is a set of activities that belong together in order to achieve a certain business goal. Activities can be completely automated or based on interaction with a human user and intellectual decision-making. In particular, an activity can spawn requests to an arbitrary "invoked application" that is provided by some server independently of the current workflow. Workflow management systems (WFMS) orchestrate the control and data flow between a workflow's activities, based on a high-level specification of the intended behavior (e.g., using Petri-net variants, state charts, or some script language) with some leeway for exception handling and run-time improvisation (as needed, e.g., in medical applications). Despite their business success, most WFMS products exhibit specific idiosyncracies and, by and large, significant deficiencies and limitations in terms of their performance. The current situation is probably comparable to that of relational database systems in the eighties. Also and similarly to database technology, configuring and tuning a WFMS for satisfactory performance falls more in the realm of black art (i.e., guesswork or expensive trial-and-error experimentation) and sorely lacks scientific foundations. Even such mundane basics such as sy...