Actually i'm new in nginx, the truth is i still don't have a plan about this.. But i have one concept to cluster every request coming from client by requested header or page. Let's say i have cluster A and cluster B. If request contains only GET method or page that only showing result from querying database i will redirect the request to cluster A. Then if request contains POST method or page that contains some form to be filled, i will redirest the request to cluster B. In fact, i will use layer 7 to read this, or maybe there is another another way to read it.
Sorry for my bad english
Sorry for my bad english