Question: What are the differences between Redis replication and standalone setup?

Answer

In a Redis standalone setup, there is only one instance of Redis running. This single Redis server handles all operations, fulfills all requests, and holds all data. Standalone setups are straightforward to manage, but they have several drawbacks. They can become a bottleneck when under heavy load, and if the single server fails for any reason, there's no redundancy to prevent data loss.

On the other hand, in a Redis replication setup, there is one primary Redis server and one or more replica servers. The primary server performs all write operations, and the replicas copy (or replicate) the data from the primary server. Read operations can be distributed across the primary and replica servers, which can significantly increase read throughput.

# Configure replication on a replica server
slaveof <masterip> <masterport>

The main advantages of Redis replication over a standalone setup are improved performance and reliability. Replication spreads the load over multiple servers, which can improve response times and overall system performance. In addition, because data is duplicated across multiple servers, it provides a level of redundancy that can protect against server failures.

However, Redis replication also has some drawbacks compared to a standalone setup. It is more complex to set up and manage, especially when dealing with failover situations. And while replication improves read performance, it does not necessarily improve write performance, since all writes still must be performed on the primary server and then replicated to the secondary servers.

To decide between a standalone and replicated setup, you should consider your application's requirements. If you need higher performance, redundancy, and are okay managing a more complex system, a replication setup might be the better choice. For simpler applications, or in development environments, a standalone setup is often sufficient.