Upstream Keepalive Questions

[abstein2]

Maxim,

Thanks so much for clarifying. Just to make sure I'm understanding
correctly, if I had something like this pseudo-code

upstream upstream1 { }
upstream upstream2 { }
upstream upstream3 { }
upstream upstream4 { }
upstream upstream5 { }

server { server_name server1.com; proxy_pass http://upstream1; }
server { server_name server2.com; proxy_pass http://upstream2; }
server { server_name server3.com; proxy_pass http://upstream3; }
server { server_name server4.com; proxy_pass http://upstream4; }
server { server_name server5.com; proxy_pass http://upstream5; }

There would only be performance degradation if the setup was:

server {
server_name server6.com;
set $PROXY_TO 'upstream5';
proxy_pass http://$PROXY_TO;
}

Is that correct? And, if there was degradation, would it be limited to hosts
that server block was trying to serve or would it impact overall
performance?

Thanks!

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,249089,249130#msg-249130