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WhatsApp handles around 10 million connections on a single server - per what unit of time?

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#1

Hello, the material says:

WhatsApp handles around 10 million connections on a single server

Then, to calculate the number of servers, it’s suggested that we get the number of daily users (2 billion) and divide by this number (10 million connections on a single server) that’s not clear, the unit of time.

Usually, the information about how much a server can handle is given by seconds. Is this assuming that is 10 milion connections per day? Even though, it doesn’t seem correct to present the information in this way. Can anyone give a help?

Course: Grokking Modern System Design Interview for Engineers & Managers - Learn Interactively
Lesson: Requirements of WhatsApp’s Design - Grokking Modern System Design Interview for Engineers & Managers

#2

Hello Amanda Varella,
Let us clarify that 10M is the number of connections a WhatsApp server can handle per second (RPS).Next, calculating the number of servers based on the number of users per second will give us a very small number. For example, 2 billion DAU, approximately becomes 23,148 users per second. Based on this estimation, we would require a single server to handle 23148 users per second, i.e., 23148/10M ~ 0.023.
This approximation is far from the realistic one; therefore, we proposed a different estimation method which gives us more realistic approximation of the number of server. You can have a look at it in the back-of-the-envelope calculation chapter to better understand its purpose. We followed the same approximation method in the WhatsApp and other design problems.

Hope this helps!