Cloud options for a replica set

We can set up and operate a replica set from our own servers, but we can reduce our operational overhead by using a DBaaS provider to do so. The three most widely used MongoDB cloud providers are Amazon’s DocumentDB, Microsoft’s Azure Cosmos DB, and MongoDB Atlas, the native offering from MongoDB, Inc.

In this section, we will go over these options and how they fare in comparison to using our own hardware and data centers.

Amazon DocumentDB

Amazon DocumentDB is a wire protocol-compatible MongoDB offering based on Amazon’s infrastructure. It offers compatibility with versions 3.6 and 4.0 of MongoDB as of summer 2022.

Amazon DocumentDB is offering what is essentially a replica set configuration with one primary for writes and up to 15 secondaries across availability zones in a single region for reads. Sharding is not supported and write scaling can only be achieved by scaling up the primary server instance. We should accordingly...