Design a geo-distributed File Storage System
Last updated: August 4, 2025
Quick Overview
Design a geo-distributed file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Notion
August 4, 202590
6
4,485 solved
Design a geo-distributed file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
ML system design at Notion goes beyond model selection. This System Design Round question evaluates your ability to design end-to-end ML pipelines, from data collection to model serving, while considering production constraints like latency and reliability.
What the Interviewer Expects
- Design the full ML lifecycle from data collection to model monitoring
- Address cold start, exploration/exploitation, and model freshness
- Discuss multi-objective optimization and ranking systems
- Plan for model debugging, fairness, and bias mitigation
- Design the feature store and training pipeline for scale
- Address model versioning, canary deployments, and rollback strategies
- Discuss the data flywheel and long-term system evolution
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 debug a model that works well offline but poorly online?
- How would you handle a 10x increase in prediction requests?
- What would you do if model performance degrades over time?
- How would you run A/B tests on different model versions?
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Requirements
Functional Requirements
- File Upload/Download: Users must be able to upload and download files seamlessly from any geographical location.
- Versioning: Implement file version control to...
Capacity Estimation
Assuming Notion has around 5 million users and each user uploads an average of 5 files per month:
- Total Files per Month: 5 million users * 5 files = 25 million files
- Daily Requests: Assumi...
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