Question: What are the differences between Redis Cluster and Master-Slave setup?

Answer

In Redis, both cluster and master-slave configurations offer ways to manage data replication and failover. However, there are several key distinctions.

Redis Master-Slave:

1. Simplicity: Setting up a master-slave configuration is simpler because it only involves replicating data from a master node to its slave nodes.
2. Single Point of Failure: If the master node fails, manual intervention may be needed for a slave to become the new master, depending on your configuration.
3. Scaling: This configuration supports read scaling by directing read operations to slave nodes. Write scaling is not supported since all write operations occur at the master node.

Here's an example of how to set this up:

# On the slave node
redis-cli SLAVEOF host master_port

Redis Cluster:

1. High Availability: Redis Cluster provides automatic partitioning across multiple nodes, which means you can have multiple master nodes, eliminating the single point of failure.
2. Failover Handling: If a master node in a cluster fails, the system automatically promotes a corresponding slave to be the new master.
3. Scaling: This setup supports both read and write scaling. Data is partitioned across multiple nodes, so write operations can be distributed.

In conclusion, while the master-slave setup is simpler to configure and sufficient for many cases, Redis Cluster offers advanced features like automatic failover and sharding that are essential for high availability and scalability.