Let’s say I have to host 25 websites… How do I know how powerful should my VPS be? Which specs it should have, how fast the connection should be to handle X visits per day?
How do you understand which are your system requirements BEFORE deploying a project? Do you just make estimates and then scale up? Or there’s some kind of tool to benchmark? how to handle this kind of stuff?
If on the public internet, also consider how your going to integrate with a CDN like Cloudflair. With luck they will serve a lot of the load and provide the DDOS protection.