This question is specific to Rackspace, but I guess it could be applied to something like AWS as well.
Say I have the following group of machines: 1 load balancing VM, 2 web VMs and a database VM. If the database is only accessed by the web machines (over an internal IP where the bandwidth usage is free) and the web machines are only accessed (by the general public) over internal IPs (again, free) via the load balancer, does this mean that the only bandwidth that I'm actually paying for is the incoming and outgoing from the loadbalancer?
Have I got that right?
Best Answer
That sounds correct as long as your load balancer is also acting as a proxy for the web servers. Only the data that goes out directly to and from the user to your servers should incur bandwidth charges, whether the packets are going through the load balancer or directly to your web servers.
Many load balancers, however, act on a strategy of forwarding the request, not proxying it. You may want to double check on a client to see which IP the packets are actually coming from.
Either way, internal traffic such as that between your web servers and your database server is safe.