alt Hacker NewsIt is often not worth optimising in the early days. You don't know how popular it will become, you might not know how many DNS records you will hold, it was possibly written in an earlier language and ported as-is.
At the point someone queries the 100TB of RAM, then maybe it is worth revisiting but even that has risks. You have to design the migration path, have fallback mechanisms etc.
It's also often that you can avoid all those future migration/fallback risks and pains if you invest a little bit of design thinking upfront.
So how would you decide which path to take in situations like this?