Design a Fault-Tolerant Distributed LLM Training Platform System Design Interview

1. Problem Statement

2. Architecture Discussion Map

Use this as one discussion aid, not a single correct answer. Your design should follow from the requirements, scale, and trade-offs you establish.

graph LR
    A["Design a Fault-Tolerant Distributed LLM Training Platform"]
    A --> F1["Parallelism strategy and topology mapping"]
    A --> F2["Input pipeline and data quality"]
    A --> F3["Checkpointing, restart, and elastic recovery"]
    A --> F4["Communication, stragglers, and performance efficiency"]
    A --> F5["Numerical correctness, observability, and reproducibility"]

3. Key Focus Areas

• 1
  Parallelism strategy and topology mapping
• 2
  Input pipeline and data quality
• 3
  Checkpointing, restart, and elastic recovery
• 4
  Communication, stragglers, and performance efficiency
• 5
  Numerical correctness, observability, and reproducibility

4. What Strong Candidates Should Demonstrate

• ✓Choose parallelism dimensions from model, memory, and interconnect constraints.
• ✓Quantify checkpoint, restart, data loading, and communication bottlenecks.
• ✓Design for expected hardware failures without sacrificing convergence correctness.

Evaluation Guide

This is an evaluation framework, not a single model answer. Strong designs may make different choices when their assumptions and trade-offs are explicit.