Buffers

Both upload rows pause after 1024 of 65536 bytes. Buffering on stops before backend-handler entry; buffering off forwards early and the handler reads one byte.

Request buffering controls when the backend receives an upload

An upload has two separate connections: client to nginx and nginx to the application. proxy_request_buffering on reads the complete client request body before sending that request upstream. Turning it off lets nginx forward body bytes as they arrive. This changes when the application becomes occupied; it does not create unlimited capacity or make a slow sender disappear. ...