My daughter runs a fan site at JonasBrothersFan.com which gets A LOT of traffic. I have it running on a dedicated box, but at the point where users online gets to over 6000 users the site stops responding to remote requests. I checked perfmon and the Current Anonymous Users counter pegs out at the top and the only thing that gets it back is to recycle the web. The site gets a lot of traffic, but the problem is its mostly kids so it peaks on weekends and after school. It gets about 200,000 page views per day, but again the traffic is clustered.

My first items is to enable caching as much as possible and turn off the logging to cut down the traffic to the SQL Server. I also enable compression, and the box still does well as far as resources go. Memory and CPU are fine, my only problem is the pegging out of the Current Anonymous Users counter which stops DNN from responding. The wierd thing is it only stops responding to external requests. If I terminal to the machine DNN still responds fine.

It looks like the problem was with a chat module called SwirlChat. It uses AjaxPro, and may not be closing connections correctly or opening new ones repeatably. Once I uninstalled the site is working again.