Replication

Partitioning can improve the scalability and performance of a system by distributing data and request load to multiple nodes.

Another dimension that benefits from using a distributed system is known as availability.

Availability

Availability refers to the ability of the system to remain functional despite failures in parts of it.

Mechanism to achieve availability

The technique we use to achieve availability is replication.

Replication

Replication is the main technique used in distributed systems to increase availability. It consists of storing the same piece of data in multiple nodes (called replicas) so that if one of them crashes, data is not lost, and requests can be served from the other nodes in the meanwhile.