Earlier quoted context omitted.
Their scale is enormous. I first heard the phrase "thundering herds" in a Facebook MySQL talk. (Thundering herds refers to what happens to your infra when something big happens in real life that lights up social networking/search/etc.)
Let's try to put a guess in numbers. > With roughly 2.85 billion monthly active users as of the first quarter of 2021 > 1.8 billion of Facebook users (66%) use the app on a daily basis Say 1 database could store the data + handle the reads/writes for 100,000 users (literally just guessing) 2.85 billion monthly active users / 100k users per server = 28,500 servers/"instances" for MySQL That's not even counting Kuberne…
https://engineering.fb.com/2019/06/06/data-center-engineerin...
Also, that "30,000 servers" number is off by... a lot. No comment on by how many orders of magnitude. :-)