Difference between FASTCGI and PROXYing

[Shehi]

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 at AppServer via Upstreaming, through port 8000.
NGinx-web-server at 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...

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,212360,212360#msg-212360