Can we do data replication in MongoDB?

A replica set in MongoDB is a group of mongod processes that maintain the same data set. Replica sets provide redundancy and high availability, and are the basis for all production deployments. This section introduces replication in MongoDB as well as the components and architecture of replica sets.

What is replication in MongoDB?

In simple terms, MongoDB replication is the process of creating a copy of the same data set in more than one MongoDB server. This can be achieved by using a Replica Set. A replica set is a group of MongoDB instances that maintain the same data set and pertain to any mongod process.

How does replication work in MongoDB data set?

Secondaries replicate the primary’s oplog and apply the operations to their data sets asynchronously. By having the secondaries’ data sets reflect the primary’s data set, the replica set can continue to function despite the failure of one or more members.

How is data synchronization done in MongoDB?

MongoDB uses two forms of data synchronization: initial sync to populate new members with the full data set, and replication to apply ongoing changes to the entire data set. Initial sync copies all the data from one member of the replica set to another member. When you perform an initial sync, MongoDB:

How are mongod instances that host the same data set?

A replica set is a group of mongod instances that host the same data set. In a replica, one node is primary node that receives all write operations. All other instances, such as secondaries, apply operations from the primary so that they have the same data set.

How to enable retryable writes in MongoDB 4.0?

MongoDB 4.0 and 3.6-compatible drivers must explicitly enable retryable writes by including retryWrites=true in the connection string. Starting in version 4.4, MongoDB provides mirrored reads to pre-warm electable secondary members’ cache with the most recently accessed data.