Upload large files via Nginx reverse proxy

[cyberfarer]

We have Nginx as a reverse proxy server to a Pydio server backend running
with Apache2. We are attempting to upload a 50G file. The Nginx server,
1.14.0, is attempting to write the file locally to /var/lib/nginx/body/
rather than sending it directly to the backend. Our proxy server has a very
small footprint of just 13G. 

Is there an option to send the file directly to the backend without writing
locally?

Thank you.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,280578,280578#msg-280578