I have a very simple configs, yet somehow i didnt get very good explanation.
Below is my configuarations

upstream backend {
      server server1.api:443 max_conns=150;
      server server2.api:443 backup;                                               }

My expectations :
So, by checking /nginx_status when the active connections exceeds 150 more connection should be routed towards server 2 right. But in actuall its not,

Also i have removed the backup from the server2 but the even my active connection in status is 20 the request still goes to server2.