System requirements

Functional:

• User can load/upload files.
• Modify content.
• Share files with permissions (Read-only/Write-only etc.).

Non-Functional:

• Availability
• Durability.
• Scalability.
• Consistency.
• Security.
• Low latency.

Capacity estimation

Estimate the scale of the system you are going to design...

API design

Define what APIs are expected from the system...

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...

High-level design

• CDN
• API Gateway - load balancer, router, auth, rate limiter and ssl termination.
• File uploader - writes metadata of file to Metadata DB and returns URL to chunk uploader.
• Chunk uploader - uploads data in blob store.
• Blob store - stores user content (AWS S3).
• Metadata - stores file metadata (Postgres).
• Sync service - synchronizes data on the server and on the client device.
• Async job - notify all devices.

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...

Trade offs/Tech choices

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

Failure scenarios/bottlenecks

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

Future improvements

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