I don't mean to be an ass, but you are not going to have 1k simultaneous users. If you did, you would be able to pay someone who had a better understanding of

I don't mean to be an ass, but you are not going to have 1k simultaneous users. If you did, you would be able to pay someone who had a better understanding of how webservers work. One decent machine running 10 mongrels on a reasonably well-designed Rails app will easily be able to handle 100 requests per second. That is more traffic than you will ever get, I guarantee you.