Hi there,

I have simple question regarding: what is the difference between these two load-balanced setups from performance perspective:

SETUP 1 - FASTCGI mode:
Machine 1 - Load Balancer:
NGinx as balancer is installed, Upstreaming is used to connect to the PHP-FPM servers below, using fastcgi_pass directive;
Machine 2 and 3: AppServers:
PHP-FPM installed. No NGinx installation;
HOW IT WORKS: Client request first comes to the Load balancer, it is redirected to AppServer using Upstreaming. Response is returned from AppServer to the LoadBalancer and to the client.


SETUP 2 - PROXY:
Load Balancer:
NGinx is installed, Upstreaming is used to redirect to the Machines below, using proxy_pass directive;
AppServers:
NGinx is installed as web-server. It listens to the incoming calls from LoadBalancer via port 8000 and relays them to the PHP-FPM via port 9000 using fastcgi_pass directive.
PHP-FPM is installed as FCGI and listens to the local NGinx-web-server via port 9000. It accepts calls from it and returns the response to it.
HOW IT WORKS: Client request first comes to LoadBalancer Nginx, and gets relayed to the NGinx@AppServer via Upstreaming, through port 8000. NGinx-web-server@AppServer receives the call from LoadBalancer and passes it via FCGI to its local PHP-FPM. PHP processes the request, and responds to the local app-server, which in return responds to the LoadBalancer. LoadBalancer answers the client's request.



Thanks and sorry for long explanations...