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...
graph TD;
A[Client Interface] --> B[API Gateway];
B --> C[Authentication Service];
B --> D[File Management Service];
B --> E[Notification Service];
D --> F[File Storage Service];
D --> G[Database];
F --> G;
E --> G;
C --> G;
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...
sequenceDiagram
participant Client
participant APIGateway
participant AuthService
participant FileService
participant StorageService
participant Database
Client->>APIGateway: Upload File Request
APIGateway->>AuthService: Authenticate User
AuthService->>APIGateway: Authentication Success
APIGateway->>FileService: Forward Upload Request
FileService->>StorageService: Store File
StorageService->>Database: Update File Metadata
StorageService-->>FileService: File Stored
FileService-->>APIGateway: File Upload Success
APIGateway-->>Client: Upload Success Response
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...
- 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.
- 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.