System requirements

Functional:

Users can upload and download files.

Store files securely.

Retrieve files upon request.

Share files with other users via links.

Notify users about shared files, changes, and updates.

Non-Functional:

Scalability: System must handle millions of users and petabytes of data.

Availability: high availability with minimal downtime.

Performance: Low latency for file upload/download.

Reliability: Data redundancy and backup mechanisms.

Capacity estimation

Users: 100 million users.

Active Users: 10 million daily active users.

Storage: 10 PB (10,000 TB) of total storage.

File Upload/Download: 1 million file uploads/downloads per day.

API Requests: 10 million API requests per day.

API design

Define what APIs are expected from the system...

POST /upload: Upload a file.

GET /download/{fileId}: Download a file.

GET /files: List user's files.

DELETE /files/{fileId}: Delete a file.

POST /files/{fileId}/share: Share a file.

GET /files/{fileId}/metadata: Get file metadata.

Database design

Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...

Users:

- userId (Primary Key)

- email (Unique)

- passwordHash

- createdAt

- updatedAt

Files:

- fileId (Primary Key)

- userId (Foreign Key)

- fileName

- fileSize

- fileType

- fileLocation

- createdAt

- updatedAt

FileVersions:

- versionId (Primary Key)

- fileId (Foreign Key)

- versionNumber

- fileLocation

- createdAt

FileShares:

- shareId (Primary Key)

- fileId (Foreign Key)

- sharedWithUserId (Foreign Key)

- permission (enum: view, edit)

- createdAt

Notifications:

- notificationId (Primary Key)

- userId (Foreign Key)

- message

- createdAt

- readAt

High-level design

You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...

File Management Service:

• Responsibilities: Handle file upload/download, metadata management, versioning, and sharing.
• Scalability: Horizontally scalable by adding more instances.
• Storage: Uses a distributed file system (e.g., Amazon S3, Google Cloud Storage).
• Algorithm: Efficient file chunking for large file uploads, deduplication to save storage space.

File Storage Service:

• Responsibilities: Store files securely and efficiently, manage file locations and redundancy.
• Scalability: Uses a distributed storage system to handle large volumes of data.
• Algorithm: Erasure coding for data redundancy and recovery, consistent hashing for load balancing.

Trade offs/Tech choices

Explain any trade offs you have made and why you made certain tech choices...

1. Tradeoffs:

• Consistency vs. Availability: Chose eventual consistency to ensure high availability and partition tolerance in a distributed system.
• Performance vs. Security: Encrypting files might add overhead but ensures data security.

1. Tech Choices:

• Database: Chose a mix of SQL and NoSQL databases for structured and unstructured data.
• Storage: Used cloud storage solutions for scalability and reliability.
• Microservices: Modular design for maintainability and scalability.

Failure scenarios/bottlenecks

Try to discuss as many failure scenarios/bottlenecks as possible.

Data Loss: Implement data redundancy and regular backups.

Service Outage: Use failover strategies and load balancing.

Security Breach: Encrypt data at rest and in transit, use robust authentication mechanisms.

Future improvements

What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?

Enhanced Search: Implement full-text search capabilities.

AI-based Features: Use machine learning for smart file recommendations and tagging.

User Analytics: Provide detailed analytics for user file activities.

Real-Time Collaboration: Enable real-time file editing and collaboration.