Architect a geo-distributed Ad Serving Engine

Last updated: November 18, 2025

Quick Overview

Design a geo-distributed ad serving system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

NVIDIA
System Design
Software Engineer
NVIDIA
November 18, 2025
Software Engineer
Onsite
System Design
Hard

2

10

3,205 solved


Design a geo-distributed ad serving system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.

System design interviews at NVIDIA typically last 45-60 minutes. You are expected to drive the conversation, starting from requirements gathering through to a detailed architecture. The interviewer will evaluate your ability to handle ambiguity and make practical engineering decisions.

What the Interviewer Expects
  • Drive the design discussion proactively with minimal interviewer guidance
  • Perform detailed capacity estimation and use it to inform design decisions
  • Design for global scale with multi-region deployment and data consistency
  • Deep dive into 2-3 critical components with implementation-level detail
  • Address complex trade-offs: CAP theorem, eventual consistency, conflict resolution
  • Discuss operational excellence: deployment strategy, chaos engineering, SLOs/SLIs
  • Propose a phased rollout plan from MVP to full-scale system
Key Topics to Cover
Load balancing and horizontal scaling
Requirements gathering and capacity estimation
Consistency models and replication
Caching strategies (local, distributed, CDN)
High-level architecture and component design
Partitioning and sharding strategies
How to Approach This
  1. Start by clarifying functional and non-functional requirements with the interviewer.
  2. Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
  3. Draw a high-level architecture first, then deep dive into 1-2 critical components.
  4. Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
  5. Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
  • How would you handle a 10x increase in traffic overnight?
  • How would you handle schema migrations with zero downtime?
  • What monitoring and alerting would you set up on day one?
  • How would you optimize costs as the system scales?
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Sample Answer
Requirements

Functional Requirements

  1. Ad Request Handling: The system must process millions of ad requests per second from various geographical locations.
  2. Geo-Targeting: Ads should be served based...
Capacity Estimation

Estimation Breakdown

  1. User Base: Assume 100 million unique users worldwide.
  2. Daily Requests: Each user generates an average of 10 ad requests per day.
  3. Total Daily Requests: 100 ...

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