This is both load balancing and a redundant load balancer. Traffic goes to all the backend web-servers under this scenario, through a single load-balancer devi

This is both load balancing and a redundant load balancer. Traffic goes to all the backend web-servers under this scenario, through a single load-balancer device/server. If that device goes down the secondary takes over. While if you have millions of requests/sec this scenario wouldn't be quite enough for you, using haproxy with carp/ucarp/keepalived will get you at least 100k connections or more. If you need millions, then you have other problems to worry about as well :).