How to set max_pool_size

Question

I have the server with linux + nginx + passenger + redmine installed.

First of all I don't know passenger installation type - nginx or standalone?

I have next lines in nginx.conf:

 upstream passenger {
       server 127.0.0.1:85;
    }

   location / { 
           root /www/redmine/public; 
       if (!-f $request_filename) {
               proxy_pass http://passenger;
               break;
           }
        }

and launch passenger from comand line:

passenger start -p 85 -d

Second question where do I need to set max_pool_size parameter? nginx.conf or somewhere else ?