What matters from a computing perspective is how many writes/second you’re doing. Keep in mind that you can keep/log aggregate or statistical data, such as min/max/average values from your PLC(s). You can also use deadbands to log significant changes. Realistically, doing anything meaningful with that much data later will be a huge challenge.
If you do in fact have a huge data requirement, I would recommend contacting Kyle. He’s pretty savvy with hardware/software/OS/database tweaks. You won’t run into Ignition licensing problems, but you may have quite a system to engineer and a lot of data to maintain.