educative.io

Educative

Can you please cover number of replicas?

In this as in other examples, it would be very helpful to have some back of the envelope calculations for number of replicas, number of application servers, number of cache servers, etc. given some assumptions. E.g. assuming each node has 1 TB of Ram and 32 cores and they are connected over 1 GBPS network, we estimate we would need 10 / 100 / 1000 machines for Instagram. Isn’t that something that will surely come up in a design interview? It’s not as simple as making a division.