The number of large-scale clusters is rising. They are included into Grids or become key components o f large structures. As more users and projects rely 071 HPC clusters, high availability and security are requirements for a fast growing adoption and use. I n this paper, ute focus o n high performance networks. All HPC clusters are built o n top of them. We demonstrate that classical instrumentation are ineficient in HPC environment, they do not scale or cause a significant loss of performance. Based 071. this fact, we highlight clusters properties: nodes have assigned roles and are coupled at various levels. Moreover, we study the main characteristics of resource usage for each type of node and propose a n instrumentation that can be effectively deployed. It results in fine-grained mechanisms adapted to system architecture and performance constraints.. Relevant information is collected over time. Two properties are verified online and dynamically: coherency and containment. Each induces a type of verification and both aim at reducin,g recovery time from failure and security risk of a whole cluster. We illustrate our. rnethodology o n QsNet network and provide a way t o increase safety of high performance networks and clusters.