>250,000 backend hits a day is a nice load, but I wouldn't call that heavy by any means.

I did a search on my post and didn't find the word "heavy". But, I assume it is meant as an interpretation of what the context is all about.

>I run 10 different ASP.NET apps on my server 3 of which generate on average 500,000 backend hits a day and much more during peaks, and the server isn't even sweating over this load. And this is on 6 year old albeit reasonably powerful machine (Quadcore, multiple drives for OS/data)...

Good

>With customers I routinely run apps that are running multiple millions of hits a day on a single moderately configured box... for light loads getting several hundred requests a second is not unheard of with IIS and ASP.NET.

Very good

>But, a lot depends on what you're doing in your backend hits. 20-25 database hits is a lot, but ultimately what matters is how long do requests take and what CPU impact do they have. You should be able to monitor CPU load which is usually a good indicator of whether your server is on its way to overload. Generally when load consistently spikes over 50% it's time to think about more hardware or load balancing of some sort.

Yes, we are watching some of that. And, yes, each hit generates a lot of hits on the SQL Server. It is also using big databases with a lot of indexes having several fields and so on. I still believe we can reach over a million with the current infrastructure.

>Luckily load balancing with IIS is pretty easy these days with Application Request Routing which is a built-in IIS load balancer that is easy to use and actually is pretty efficient. So there are fairly easy scalability options available.

But, for that, I believe we need IIS 7. Is that correct?