Managing Large Scale File Uploads: Streaming to S3 vs Local Buffering

Never buffer large files in RAM; use busboy or multer to stream multipart data directly to cloud storage (AWS S3) using Managed Upload streams.

If 10 users upload 1GB files simultaneously, and you buffer them in memory, your Node.js process will crash. Instead, pipe the incoming HTTP request stream directly to the S3 SDK's upload() method. This uses 'Multipart Upload' internally, sending chunks as they arrive from the network.