I confused myself thinking about Load Balancers yesterday 😵💫
Here's the question that came to my mind:
If a Load Balancer (LB) routes users to the nearest server for low latency... And I'm in Bangladesh requesting from an LB hosted in USA...
Doesn't my request look like this:
Me (BD) → LB (USA) → Server (BD) → LB (USA) → Me (BD)
That's more latency, not less! 🐌
So should we have LBs in every region? But then... how does a user know which LB to connect to? 🤔
Do we need a Load Balancer for Load Balancers? 😅
The Answer
The answer: Yes. And it already exists. It's called DNS (Domain Name System).
Here's what actually happens:
- You type
example.com - DNS sees your IP is from Bangladesh
- DNS returns the IP of the BD load balancer
- You connect directly to BD, no USA roundtrip!
Your friend in USA? DNS gives them the USA server IP.
Why do we need both?
But wait, then why do we even need Load Balancers? 🤔
Because DNS and LB solve different problems:
- DNS = Which datacenter? (geographic, cached for hours)
- LB = Which server in that datacenter? (real-time, health-aware)
DNS is like GPS saying "go to Dhaka Medical Hospital." LB is the reception desk saying “Floor 10, Room 5, Dr. Rahman is free."
GPS doesn't know which doctor is available. Reception doesn't help you find the hospital.
You need both.
Conclusion
Sometimes the best way to learn system design is to confuse yourself with a silly question and then dig your way out. 😎