Architect a low-latency File Storage Engine
Last updated: August 4, 2025
Quick Overview
Design a low-latency file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Roblox
August 4, 202513
8
341 solved
Design a low-latency file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
ML system design at Roblox goes beyond model selection. This Onsite 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
- 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 the cold start problem?
- How would you ensure fairness and reduce bias in the model?
- How would you run A/B tests on different model versions?
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Requirements
Functional Requirements:
- File Storage: The system must support storage of various file types (images, audio, 3D models) used within Roblox.
- Low-Latency Access: Requests for file retr...
Capacity Estimation
Assuming Roblox has approximately 200 million active users, and each user generates around 100 requests for file access daily:
- Daily Requests: 200M users * 100 requests/user = 20 billion request...
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