Every September, our site experiences traffic surge that lasts for about 1-2 days. We're listed #1 on Google for keywords that a large number of people search during those days. Until last year, we were on vBulletin and the site would go down intermittently because of the traffic. This year, we're on Xenforo and can't wait to see how XF performs under load. The traffic spike would be 4-6x our regular traffic and I expect about 4k-6k simultaneous visitors (not logged in members) during the peak hours. We currently have a cloud server with 8GB RAM that handles WordPress + Xenforo gracefully and the load varies between 0.5 - 2 or 4 during peak traffic hours. I'm considering CDN integration to take some load off the servers. Do you have any suggestions on how to go about handling the load?