Should I use single node replica set for production?

[Stennie_X (Stennie)]

Hi @Daniel_Camarena,

@Daniel_Camarena

thank you for the explication. But exactly there is my doubt: The MongoDB doesn’t state clearly that I should use 3 nodes for production. It states that I should use a replica set for production, which could be perfectly a single node replica set.

You should read “replica set” as “minimum three member replica set” unless otherwise specified. The MongoDB manual does not encourage creating single member replica sets and always describes these as a group of mongod processes. The design intent of replica set deployments is to achieve all of the benefits I mentioned.

Per Replica Set Members:

The minimum recommended configuration for a replica set is a three member replica set with three data-bearing members: one primary and two secondary members.

There are other suboptimal replica set configurations like adding an arbiter (see Replica set with 3 DB Nodes and 1 Arbiter - #8 by Stennie_X for some caveats) or having less than three members.

@Daniel_Camarena

Why should I have 3 nodes competing for the same resources on the same physical machine, if one node is doing the same job perfectly?

A single node replica set does not provide the same benefits as three members, but you can choose this deployment if the caveats are acceptable for your use case.

The difference is a recommended configuration for general production use cases versus a possible configuration for your specific requirements. It sounds like you are fine with a single node replica set.

Regards,
Stennie