Design a large-scale Video Streaming Platform
Last updated: November 28, 2025
Quick Overview
Design a real-time video streaming system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Databricks
November 28, 202532
6
681 solved
Design a real-time video streaming system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Databricks asks this during the System Design Round to assess your understanding of the full ML lifecycle. They want to see how you translate a business problem into an ML objective, design the feature pipeline, and plan for model monitoring and retraining.
What the Interviewer Expects
- Define clear ML objectives with appropriate loss functions and metrics
- Design a comprehensive feature engineering pipeline
- Discuss model selection with trade-offs (complexity vs interpretability vs latency)
- Plan online and offline evaluation strategies including A/B testing
- Address serving infrastructure: batch vs real-time, latency requirements
- Consider data quality, labeling strategy, and feedback loops
Key Topics to Cover
How to Approach This
- Start by clarifying functional and non-functional requirements with the interviewer.
- Estimate the scale: QPS, storage, bandwidth. This drives your design decisions.
- Draw a high-level architecture first, then deep dive into 1-2 critical components.
- Discuss trade-offs explicitly (e.g., consistency vs availability, SQL vs NoSQL).
- Address failure scenarios, monitoring, and how the system handles 10x traffic spikes.
Possible Follow-up Questions
- How would you handle a 10x increase in prediction requests?
- How would you run A/B tests on different model versions?
- What would you do if model performance degrades over time?
- How would you debug a model that works well offline but poorly online?
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Requirements
Functional Requirements
- Real-time Streaming: Support live video streaming with low latency (under 2 seconds).
- Video On-Demand: Users can request previously recorded videos and stream...
Capacity Estimation
Assuming an average of 10 million concurrent viewers:
- Video Bitrate: Assume an average video bitrate of 4 Mbps for HD streaming.
- Data Transfer: Each user consumes approximately 2 GB of d...
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