Decision HPC 3.0 must consider an hierarchical design for scalability, and interoperability with the existing DCN architecture. HPC 3.0 must consider connectivity to storage as well as the network, all through the same fabric. Current industry best practice has proven that a tiered approach allows for greater flexibility and scalability. This is no different in the case of an HPC 3.0 design. 13.4 HPC case study Let us take a look into one potential growth path from a traditional DCN to an HPC cluster environment. To do this, we will start by considering a data center that already has a storage fabric and the decision is made to investigate how HPC benefits the business. We then investigate a potential scenario of replacing the storage on the fabric and migrating to HPC 3.0. This is not the only way to achieve the desired results, but the intent is to show the scalability available when the architect can look ahead to the future. 13.4.1 Deploying HPC 2.0 with an existing storage fabric In this case the architect has been requested to investigate the ability to deploy an HPC environment for the development team to utilize. This will allow the development team to start working HPC into their application well before deployment. Type Design decision Problem statement and questions How can the HPC be designed to integrate with the existing infrastructure in the data center? How can the HPC design allow scalability for the future? How can the HPC be deployed without the need to train staff in new network technology? Assumptions We make the following assumptions: The data center already utilizes a separate storage fabric. We assume that the corporate direction is to continue utilizing this storage infrastructure. Network delivery staff are already familiar with Ethernet technology and have worked with various Ethernet connectivity options before (RJ45, Cat6, SFP, XFP, Fiber). Chapter 13. Network design for high performance computing 291