Publications

Carnac, located at Sandia's California site, is an institutional cluster for Emulytics that provides security researchers with resources to model enterprise computer networks and evaluate how resilient they are from attacks. While multiple Emulytics cluster computers have been built at Sandia, Carnac is the first system that was developed as an institutional resource that can be shared among different groups with disparate requirements.

Priority-based Flow Control (PFC), RDMA over Converged Ethernet (RoCE) and Enhanced Transmission Selection (ETS) are three enhancements to Ethernet networks which allow increased performance and may make Ethernet attractive for systems supporting a diverse scientific workload. We constructed a 96-node testbed cluster with a 100 Gb/s Ethernet network configured as a tapered fat tree. Tests representing important network operating conditions were completed and we provide an analysis of these performance results. RoCE running over a PFC-enabled network was found to significantly increase performance for both bandwidth-sensitive and latency-sensitive applications when compared to TCP. Additionally, a case study of interfering applications showed that ETS can prevent starvation of network traffic for latency-sensitive applications running on congested networks. We did not encounter any notable performance limitations for our Ethernet testbed, but we found that practical disadvantages still tip the balance towards traditional HPC networks unless a system design is driven by additional external requirements.

In this document we describe a reference architecture developed for Emulytics^TM clusters at Sandia National Laboratories. Taking into consideration the constraints of our Emulytics software and the requirements for integration with the larger computing facilities at Sandia, we developed a cluster platform suitable for use by Sandia's several Emulytics toolsets and also useful for more general large-scale computing tasks.

Abstract not provided.