Design a real-time File Storage System
Last updated: August 20, 2025
Quick Overview
Design a real-time file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
Instacart
August 20, 20254
12
2,421 solved
Design a real-time file storage system that handles millions of requests. Discuss trade-offs in consistency, availability, and performance.
This is a common system design question asked during Onsite at Instacart. The interviewer expects you to demonstrate your ability to design large-scale distributed systems, make well-reasoned trade-offs, and communicate your thought process clearly. Instacart values engineers who can think about scalability from day one.
What the Interviewer Expects
- Clearly define functional and non-functional requirements
- Propose a reasonable high-level architecture with core components
- Choose appropriate data storage solutions with basic justification
- Discuss basic scaling strategies (horizontal scaling, caching)
- Identify potential bottlenecks and suggest simple solutions
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
- What monitoring and alerting would you set up on day one?
- How would you implement rate limiting to protect the system?
- How would you handle a 10x increase in traffic overnight?
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Requirements
Functional Requirements
- File Upload/Download: Users should be able to upload and download files in real-time.
- Version Control: Maintain multiple versions of files for rollback capabi...
Capacity Estimation
Assuming Instacart handles approximately 10 million file upload/download requests daily:
- Requests per second: 10 million requests / 86400 seconds = ~115.74 requests per second.
- **File Size:*...
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