Design a File Storage Service
Last updated: March 9, 2026
Quick Overview
Design a event-driven file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Robinhood
System Design
Product Manager
Robinhood
March 9, 2026Product Manager
Technical Screen
System Design
Medium
133
12
2,538 solved
Design a event-driven file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Robinhood asks this during the Technical Screen to assess your architectural thinking. They want to see how you decompose a complex problem, choose appropriate technologies, and reason about failure modes. Strong candidates proactively discuss monitoring, alerting, and operational concerns.
What the Interviewer Expects
- Systematically gather requirements and estimate capacity (QPS, storage, bandwidth)
- Design a scalable architecture with clear component responsibilities
- Make well-reasoned database and caching decisions with trade-off analysis
- Address consistency vs availability trade-offs specific to the use case
- Discuss partitioning strategy, replication, and data modeling
- Cover failure handling, monitoring, and alerting strategies
Key Topics to Cover
Security and authentication
Requirements gathering and capacity estimation
High-level architecture and component design
Consistency models and replication
Database selection and data modeling
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
- What happens if one of your database nodes goes down?
- How would you handle schema migrations with zero downtime?
- How would you implement rate limiting to protect the system?
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Requirements
Functional Requirements
- User File Uploads: Users should be able to upload various file types (images, PDFs, etc.) with a maximum file size of 100 MB.
- File Retrieval: Users should be ...
Capacity Estimation
Back-of-Envelope Calculations
- User Base: Assume 10 million active users.
- File Uploads: Each user uploads an average of 2 files per week. Thus, total uploads per week = 10M users * 2 fi...
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