How do you enable the MongoDB oplog?
To enable MongoDB oplog, you need to follow these steps:
- Enable replication mode in the MongoDB configuration file. Open the configuration file (typically mongod.conf) and set the replSet option to the name of the replica set. For example:
- The replication set is named myReplicaSet.
- Restart the MongoDB service to apply the changes made to the configuration file.
- Connect to the MongoDB server and initialize the replica set with the command rs.initiate(). For example, run the following command in the MongoDB shell:
- initialize replication set
- If there are already other MongoDB instances running, you can use the rs.add() command to add them to the replica set. For example, running the following command will add another MongoDB instance to the replica set:
- Add the server “mongodb2.example.com” with port 27017 to the replica set.
- Confirm that the replica set has been configured and all members have been added. Use the command rs.status() to check the status of the replica set.
- Enable the oplog for the replica set. Run the following command in the MongoDB shell:
- Create a collection named “oplog.rs” locally with capped size equal to
. - The oplog size refers to the maximum size of the oplog, typically set to be large enough to meet the needs of the application (e.g. 100 MB or 1 GB).
- Configure MongoDB to allow access to the oplog from all hosts. Edit the MongoDB configuration file and set security.authorization to disabled and net.bindIp to 0.0.0.0 respectively.
- Restart the MongoDB service to apply the changes made to the configuration file.
The oplog of MongoDB should now be activated and accessible on the primary node of the replica set.
