The interesting properties of P2P systems (high availability despite peer volatility, support for heterogeneous architectures, high scalability, etc.) make them attractive for distributed computing. However, conducting large-scale experiments with these systems arises as a major challenge. Simulation allows only to partially model the behavior of P2P prototypes. Experiments on real testbeds encounter serious difficulty with large-scale deployment and control of peers. This paper shows how an optimized version of the JXTA Distributed Framework (JDF) can help deploying, configuring and controlling P2P experiments. We report on our experience in the context of our JUXMEM JXTA-based grid data sharing service for various configurations. 1 How to test P2P systems at a large scale? The scientific distributed systems community has recently shown a growing interest in the Peer-to-Peer (aka P2P) model [1]. This interest is motivated by properties exhibited by P2P systems such as high availab...