Question: What is the default replication behavior in Redis?

Answer

In Redis, replication is a feature that allows data from one Redis server (commonly known as the master) to be mirrored to any number of other Redis servers (known as slaves). Replication is used for performance optimizations and data redundancy.

By default, Redis does not have replication enabled. To activate it, you would need to explicitly configure it in your setup.

For instance, to set up a slave Redis server, you would use the SLAVEOF command followed by the hostname and port of the master server:

SLAVEOF master_host master_port

To revoke the replication, use the same SLAVEOF command followed by 'no one':

SLAVEOF NO ONE

Keep in mind that Redis uses asynchronous replication, meaning that the master will continue to handle queries without waiting for the slaves to update. Also, starting from version 3.0, Redis supports automatic partitioning with the introduction of Redis Cluster, providing a more robust solution for handling larger datasets across multiple nodes.