I have a Rackspace load balancer running a couple of servers. Before I update my site and restart the web server I drain the connections to one of the servers but I'm not sure when the server is completely drained. Is there a way to tell?
netstat , for example:
netstat -tapn |grep -c nginx to check how many connections (plus one listening) you have on nginx (or apache2 etc), you can also grep for the different (ESTABLISHED etc) statuses.
You could besides follow the tail of your web server's access log (for ex:
tail -f /var/log/nginx/access.log ) to see if there are more requests coming in.