Interview Questions

By Ravindra Bagale Last updated: 3 October 2026

These RDS questions come up in cloud interviews. In every answer, be clear about the endpoint, the security group, and how backups work.

Q1. What does RDS manage, and what do you still manage?: RDS installs, patches, backs up and can fail over the database engine. You still design the schema, write SQL, set the security group, and put the endpoint, user and password in the application.
Q2. Why is Public access set to No, and why do you still edit a security group?: No public access means there is no public IP. The security group still decides which private clients may open port 3306. Allow only the EC2 security group, never 0.0.0.0/0.
Q3. What is a DB subnet group?: The subnets, in at least two Availability Zones, where RDS may place the database. The database is not stored on your EC2 instance.
Q4. What is the difference between an automated backup and a manual snapshot?: Automated backups (a daily snapshot plus logs) enable point-in-time restore inside the retention window, and they expire. A manual snapshot stays until you delete it. Restoring either one creates a new instance with a new endpoint.
Q5. Does a snapshot include parameter-group changes?: No. The snapshot is the data on the storage volume. Parameter groups and option groups are chosen again at restore time. If you do not choose them, RDS applies the defaults.
Q6. How is Multi-AZ different from a read replica?: Multi-AZ is a synchronous standby behind the same endpoint, for automatic failover. You do not query the standby. A read replica is an asynchronous copy with its own endpoint, for read scaling, and you can promote it to a standalone database.
Q7. What happens if you stop an RDS instance and forget it?: Storage is still charged while it is stopped. If you do not start it, RDS starts it automatically after 7 days so it can receive maintenance. Deleting is a separate step. For a lab, decline the final snapshot, and delete leftover manual snapshots yourself.