I found this question previously asked and answered on this topic: Sitecore Analytics Location has no data.
As a follow-up to that, if I just purchased the GeoIP service and turned on the Analytics.PerformLookup setting, does data capture of the GeoIP information begin from that point in time, or does Sitecore go back through Mongo and process that information from the day of inception? That is, did Sitecore care about GeoIP data prior to the activation of the service or not?
Second, to confirm what some blogs mentioned on the topic (such as https://blog.horizontalintegration.com/2016/08/28/sitecore-8-geo-ip-lookup-configuration-tips/), I only turned on Analytics.PerformLookup on my CM server, and not my CD servers. Is this the correct setup for optimal usage in a CM with two CD setup?