Designing a file sync service in which a user can upload a file to the cloud and it gets sync across all of his/her devices.
The core of this system finds its application in messaging apps as well.
The problem statement is something to start with, be creative and dive into the product details and add constraints and features you think would be important.
- Sync all the files across all the devices of the user
- A file could be at max 4GB big
- The upload and downloads should be efficient and resumable
- User's bandwidth is critical, so be efficient.
- make your high-level components operate with high availability
- ensure that the data in your system is durable, not matter what happens
- define how your system would behave while scaling-up and scaling-down
- make your system cost-effective and provide a justification for the same
- describe how capacity planning helped you made a good design decision
- think about how other services will interact with your service
- ensure the data in your system is never going in an inconsistent state
- ensure your system is free of deadlocks (if applicable)
- ensure that the throughput of your system is not affected by locking, if it does, state how it would affect
Create a design document of this system/feature stating all critical design decisions, tradeoffs, components, services, and communications. Also specify how your system handles at scale, and what will eventually become a chokepoint.
Do not create unnecessary components, just to make design look complicated. A good design is always simple and elegant. A good way to think about it is if you were to create a spearate process/machine/infra for each component and you will have to code it yourself, would you still do it?
To understand the nuances and internals of this system, build a prototype that
- does resumable upload and download
- effficiently identifies and shares changes with other devices
This is a recommended tech-stack for building this prototype
| Which | Options |
|---|---|
| Language | Golang, Java, C++ |
These are the common pitfalls that you should keep in mind while you are building this prototype
- transferring 4GB file in one call is prone to disruptions
- designing resumable uploads and downloads
- efficiently communicate changes and updates across clients
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This assignment is part of Arpit's System Design Masterclass - A masterclass that helps you become great at designing scalable, fault-tolerant, and highly available systems.