What is Distributed Systems

Definition

A distributed system is a collection of independent computers that work together and appear to users as a single coherent system, coordinating over a network to share workloads and data so they can scale beyond, and remain available despite the failure of, any single machine.

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Scale horizontally by adding machines rather than enlarging one server
Stay available despite individual node failures through redundancy
Process huge workloads in parallel across many machines
Serve users from multiple locations to reduce latency

Real World Example

A global web service runs across hundreds of servers in multiple regions so it scales to millions of users and keeps running even when individual machines or an entire data centre fails.

FAQs

What is a distributed system?

A set of independent computers coordinating over a network to act as one system, sharing work and data for scale and resilience.

Why are distributed systems hard?

Network failures, partial outages, consistency, and coordination across nodes introduce complexity not present in single-machine systems.

What is the CAP theorem?

It states a distributed system can guarantee at most two of consistency, availability, and partition tolerance simultaneously, forcing design trade-offs.