I'm just curious. How did you come up with the 16 hits/sec figure? Was it just by examining your access logs?
That's why I mention "during one hour" in my original message, it's not very clear, indeed but that's how I came up with these figures.
Just as an example, on Nov 21st, between 1pm and 2pm we had 71304 hits, that comes to 19.8 hits per second. Our load balancer never serves content from two servers at the same time, always from *one* :( That's one of the problems we are facing, it should "distribute" the load among the two machines. I think we could serve more hits per second if our load balancer was acting in a different way ;)