DSA TrainerSystem Design · Unit 9
Load balancing
You met the load balancer in the request path: the single front door that spreads requests across a pool of servers. It is worth a unit of its own, because "put a load balancer in front" is one of the most common moves you will make in an interview, and interviewers will push on the details.
A load balancer does two big jobs. It shares load, so no one server is overwhelmed and you can grow by adding servers. And it improves availability, by noticing when a server is unhealthy and routing around it so users do not hit the dead one.
This unit covers how it decides where to send each request, how it detects failure, and the follow-up interviewers love: "isn't the load balancer itself a single point of failure?"
The rest of the System Design course is premium
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