The official public answer is "millions of servers" (see, for example, https://engineering.fb.com/2018/07/19/data-infrastructure/location-aware-distribution-con

The official public answer is "millions of servers" (see, for example, https://engineering.fb.com/2018/07/19/data-infrastructure/location-aware-distribution-configuring-servers-at-scale/ https://engineering.fb.com/2018/07/19/data-infrastructure/lo...). Keep in mind that this includes Instagram and Whatsapp too, as far as I know. As for "wasteful", well.. 1.88 billion DAU (Q1 earning report) / 86400 = 21759 "users per second" (note: I made this up) Multiply that by N where N is the number of frontend and backend queries it takes to service one user, and you have a lot of QPS. Now add in headroom, redundancy, edge POPs and CDN to put servers as close to users as possible, etc. It's hard to fathom just how big traffic to FAANG services can be, until you see what it takes to serve it. Is there some waste? Sure, probably, but not as much as you'd think.