Hi,

I use Nginx (1.21.0) as an upstream proxy for a node GraphQL backend running on the same instance. I get occasional "an upstream response is buffered to a temporary file" entries in the Nginx error log. I would like to understand if that's a bad or neutral thing and, if applicable, how I can improve my config.

If I've understood correctly, proxy buffering can occur if the client's connection is slower than what the upstream server can deliver. That sounds like a pretty normal situation to me especially when clients are mobile apps like in our case. But is there something more to this?

fastcgi_keep_conn on;
fastcgi_buffers 256 16k;
fastcgi_max_temp_file_size 0;

Oops...I included the wrong Nginx config parameters in my previous post. :)

proxy_buffering on;
proxy_buffers 16 16k;
proxy_buffer_size 16k;
proxy_busy_buffers_size 16k;
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_cache_bypass $http_upgrade;