Twitter can't afford a 1:1 replica for sure, and it would be meaningless without globally distributed production load anyway.
A 1:10 replica is fine, but also astronomically expensive. What's better about it than 1:100? Or 1:10000?
Once you give up on 1:1 (which is reasonable), you're either testing in production or not really testing at all. You'll have many lines of code that will only apply to the 1:1 scale.
A 1:10 replica is fine, but also astronomically expensive. What's better about it than 1:100? Or 1:10000?
Once you give up on 1:1 (which is reasonable), you're either testing in production or not really testing at all. You'll have many lines of code that will only apply to the 1:1 scale.