Handling Large Files
Last Updated: December 28, 2025
A user tries to upload a 2 GB video file. After 45 minutes at 80% progress, their connection drops. They have to start over from scratch.
Meanwhile, your server is struggling. Memory usage spikes as it tries to buffer the entire file. The request times out. Other users experience slowdowns because one large upload is hogging resources.
This is the reality of naive file handling. And it gets worse at scale.
Every major platform, from Dropbox to YouTube to Google Drive, has had to solve this problem. The good news is that the solutions are well-established patterns that you can apply to any system that handles files larger than a few megabytes.
In this chapter, we will walk through these patterns step by step. We will start with understanding why simple approaches break down, then build up to production-grade solutions for both uploads and downloads.
Where This Pattern Shows Up
Large file handling is essential for any system that deals with media, documents, or data transfers:
| Problem | Why Large File Handling Matters |
|---|---|
| Design Google Drive/Dropbox | Users upload multi-GB files that need chunking, resume, and sync |
| Design YouTube | Video uploads can be hours long, requiring resumable uploads and transcoding |
| Design Slack/Teams | File sharing in chat requires efficient upload and CDN distribution |
| Design GitHub | Large repos with binary assets need efficient storage and cloning |
| Design Backup System | Terabytes of data require incremental uploads and deduplication |
| Design Netflix | Streaming large video files needs range requests and adaptive bitrate |