AWS Certified Solutions Architect – ProfessionalAccelerate Workload Migration and ModernizationHard

A research institution is migrating a high-performance computing (HPC) cluster to AWS. The cluster consists of tightly coupled applications that require ultra-low latency networking (sub-millisecond) and high inter-node bandwidth for inter-process communication (MPI). The existing on-premises cluster uses InfiniBand interconnects. Which AWS EC2 instance type and networking feature combination BEST meets these demanding requirements?

  1. AC7g instances with Elastic Network Adapters (ENA)
  2. BR6gn instances with ENA Express
  3. CM6i instances with Enhanced Networking (Intel 82599 Virtual Function)
  4. DHpc6a instances with Elastic Fabric Adapter (EFA)
Show answer & explanation

Correct answer: D. Hpc6a instances with Elastic Fabric Adapter (EFA)

Hpc6a instances are specifically designed for HPC workloads, offering high core counts and memory. The Elastic Fabric Adapter (EFA) is a network interface that enables HPC applications to achieve lower and more consistent latency and higher throughput than traditional TCP networking, similar to on-premises HPC clusters with InfiniBand, making it ideal for tightly coupled MPI workloads.

Why the other options are wrong

  • A. C7g instances are general-purpose compute-optimized (Graviton3) and ENA provides good networking, but not the ultra-low latency and high bandwidth required for tightly coupled HPC with MPI.
  • B. R6gn instances are memory-optimized (Graviton2) with good networking (ENA Express for higher bandwidth), but EFA is the critical component for the specific inter-process communication requirements of tightly coupled HPC.
  • C. M6i instances are general-purpose and Enhanced Networking (VF) is an older term for improved networking, not specific to the ultra-low latency and high bandwidth of HPC via EFA.

Elastic Fabric Adapter (EFA)

A network interface for Amazon EC2 instances that enables customers to run applications requiring high levels of inter-node communications at scale on AWS, like HPC and machine learning.

  • Provides lower and more consistent latency than traditional TCP.
  • Supports OS-bypass capabilities for MPI and NCCL.
  • Similar performance to on-premises InfiniBand networks.

Memory trick: EFA gives your HPC apps 'Extra Fast' networking, like InfiniBand.

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