> For the complete documentation index, see [llms.txt](https://eric-zhang-seattle.gitbook.io/mess-around/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://eric-zhang-seattle.gitbook.io/mess-around/scenarios/overview-2.md).

# GoogleDrive

* [Functional requirements](#functional-requirements)
  * [Core](#core)
  * [Optional](#optional)
* [Non-Functional requirements](#non-functional-requirements)
  * [High performance](#high-performance)
  * [Reliable storage](#reliable-storage)
  * [High availability](#high-availability)
  * [Data security](#data-security)
  * [No duplication](#no-duplication)
  * [Real world practices](#real-world-practices)

## Functional requirements

### Core

* File upload
* File download
* File continue uploading/downloading on interruption

### Optional

* File sharing
* Speed control to prioritize paid users

## Non-Functional requirements

### High performance

* 10^8 TB storage space, 10^4 average QPS, 80 Gb/s

### Reliable storage

* Files don't get lost. Reliability reaches 99.9999%, 1 lost file among 1 million files.

### High availability

* 99.99% availability per year. Less than 53 minutes downtime per year.

### Data security

* Files are encrypted when stored on the web server. People other than the user itself and shared ones could not read the file.

### No duplication

* If the same file is uploaded by two different users, the later does not need to upload again from the beginning.

### Real world practices

* <https://www.infoq.com/presentations/dropbox-infrastructure/>
  * [How do we scale Dropbox slides](https://github.com/DreamOfTheRedChamber/system-design-interviews/tree/b195bcc302b505e825a1fbccd26956fa29231553/files/QConSF2016-PreslavLe-ScalingDropbox.pdf)
  * [Dropbox security whitepaper](https://www.dropbox.com/static/business/resources/Security_Whitepaper.pdf)
  * [S3 design](https://www.youtube.com/watch?v=UmWtcgC96X8)