This is based upon the DNN version, the caching, the hardware you are running and the infrastructure, number of requests per second and exactly what you have running on each page(how much dynamic content).

Perhaps someone who is running or has developed a large DNN install can illuminate this subject with some facts.

In my estimation, if you had a *normal* webserver, you should be able to put as many pages into the DB as you like.  Spacewise SQL Server can use databases hundereds of GB in size.  It's more important how many requests you are getting per second, and how much work each page has to do in order to render.

To get an accurate estimation, set up a server with typical pages and load test it.  You can then extrapolate the hardware required based on your expected traffic levels.

Cheers,

Lance

Thank you guys very much.  What you both said put it into perspective and makes sense now.