I'm about to launch an ecommerce site in the models of eBay (to put it in the simplest possible way) and I need to know if there's a way to estimate what my site stats will be for the first month or so -and by that I mean page views, number of registered users and so on. I need to know what kind of server specs I'll need, and I honestly don't have much of an idea on that. At one of the companies I checked it says that 16 GB of RAM and 400 GB is "Ideal for complex web apps, multiple busy sites, forums or web shops." (http://vps.net/products/ssd-vps), but, like I said, I have no idea.
WP Engine (another hosting company) sent me a questionnaire to know what my necessities are, asking things such as my number of visitors per month, registered users, etc.. Is there any way to have at least some sort of estimative, so I can provide them with this info? From the companies I've seen so far, they seem to offer the best plan for me, since I want to start small and need the possibility to expand indefinitely. Their business plan has unlimited bandwidth, unlimited storage and they adapt the RAM use on a per case basis, with the servers being fully managed by them.