Managing MongoDB Config Servers

In a MongoDB sharded cluster, config servers store metadata and configuration settings. This lesson covers the management of these config servers, including their setup, operations, and best practices.

Config servers are a critical component of MongoDB sharded clusters. They store:

• Cluster metadata (e.g., shard locations)
• Configuration settings for the cluster

Typically, a replica set of config servers (3 members) is recommended for high availability.

Follow these steps to set up MongoDB config servers:

1. Install MongoDB on your servers.
2. Configure the mongod instances for config servers:

storage:
  dbPath: /data/configdb
net:
  bindIp: localhost
  port: 27019
replication:
  replSetName: configReplSet

3. Start each config server with the configuration file:

mongod --config /path/to/config.conf

4. Initialize the config server replica set:

mongo --port 27019
> rs.initiate()

Perform the following operations on config servers:

• Check status: Use rs.status() to check the replica set status.
• Add a member: Use rs.add("hostname:port") to add a new config server.
• Remove a member: Use rs.remove("hostname:port") to remove a config server.

To ensure optimal performance and reliability of your config servers, consider the following best practices:

• Maintain three config server instances in a replica set.
• Ensure config servers are on dedicated hardware or instances, separate from application data.
• Regularly back up your config server data.
• Monitor performance metrics to detect potential issues early.