Each individual computer in the group is called a node. These nodes handle their own pieces of work while staying connected to the rest of the team.

Computers as Nodes

Since the computers are separate, they must send messages to each other over a network. This allows them to share information and coordinate their actions.

Talking Over the Network

You can increase the system's power by adding more computers rather than just buying one giant, expensive machine. This is called scaling out.

Growing with More Machines

The system is designed so that if one computer breaks, the others take over its work. This ensures the entire service doesn't crash just because of one small error.

Surviving System Failures

Important information is often copied across several computers. This prevents data loss and makes it faster for users to access information from a nearby machine.

Keeping Multiple Data Copies

To handle massive amounts of data, the system splits the information into smaller chunks. Each computer manages its own specific slice of the total work.

Dividing Large Workloads

Because there are many computers, they must use specific rules to agree on decisions, like who is the boss. This prevents the computers from making conflicting choices.

Coming to an Agreement

The system tries to make sure that if you change a piece of data on one computer, all the others show that same change. This prevents people from seeing outdated information.

Keeping Everyone in Sync

The goal is for the system to be ready to help a user at any time. Even during repairs or high traffic, the service should remain accessible.

Staying Always Online

A special director directs incoming requests so that no single computer gets overwhelmed. This ensures every machine does its fair share of the work.

Balancing the Workload

It takes time for messages to travel between computers over a network. Minimizing this delay is crucial for making the system feel fast and responsive.

What is the Delay?