Master AWS DocumentDB: Key Interview Questions Explained

Interview, AWS, AWS By May 24, 2023 No Comments

I have compiled a list of top 10 AWS DocumentDB interview questions and their answers:

  1. What is Amazon DocumentDB?

Answer: Amazon DocumentDB is a managed, scalable, and highly available NoSQL database service designed to store, query, and index JSON-like data. It is compatible with MongoDB, allowing developers to use the same drivers and tools they are already familiar with while benefiting from the scalability and performance of a cloud-native database.

  1. How does DocumentDB differ from other AWS databases like DynamoDB or RDS?

Answer: DocumentDB is designed specifically for document-based data storage and querying, while DynamoDB is a key-value and document store, and RDS is a relational database service. DocumentDB provides compatibility with MongoDB, which makes it suitable for developers already familiar with the MongoDB ecosystem.

  1. What is the storage model of AWS DocumentDB?

Answer: DocumentDB uses a distributed, fault-tolerant, and self-healing storage system. The data is automatically replicated across multiple Availability Zones, providing high durability and availability. DocumentDB supports up to 15 read replicas for read-heavy workloads and scales storage automatically, up to 64 TB per cluster.

  1. How is data consistency maintained in DocumentDB?

Answer: DocumentDB provides tunable read consistency levels. By default, it offers “eventual consistency,” where read replicas might return slightly outdated data. If stronger consistency is required, you can choose “session consistency” or “strong consistency,” which ensures that reads return the latest written data.

  1. What are the backup options available in DocumentDB?

Answer: DocumentDB offers continuous, automated backups with point-in-time recovery. You can restore your cluster to any second in the last 35 days. Additionally, you can create manual snapshots for long-term storage or migration purposes.

  1. How can you migrate data to and from DocumentDB?

Answer: You can use AWS Database Migration Service (DMS) to migrate data to and from DocumentDB. DMS supports migration from various source databases, including MongoDB, to DocumentDB. You can also use native MongoDB tools like mongodump and mongorestore for migration.

  1. What are some common use cases for DocumentDB?

Answer: Common use cases for DocumentDB include content management systems, user profiles, catalogs, and configuration management. Its flexible schema and JSON-like data structure make it suitable for applications requiring complex, hierarchical, and varying data structures.

  1. How do you monitor and optimize performance in DocumentDB?

Answer: You can use Amazon CloudWatch to monitor key performance metrics, such as CPU utilization, free storage, and query latency. To optimize performance, you can use features like indexes, read replicas, and configuring the appropriate instance types for your workload.

  1. How do you secure data in DocumentDB?

Answer: Data in DocumentDB is secured using multiple methods, including encryption at rest using AWS Key Management Service (KMS), encryption in transit using TLS, and network isolation using Amazon VPC. Additionally, you can use AWS Identity and Access Management (IAM) to manage access control.

  1. How do you scale a DocumentDB cluster?

Answer: DocumentDB automatically scales storage as needed, up to 64 TB per cluster. To scale reads, you can add up to 15 read replicas. For write scaling, you can partition your data using sharding, although this is not a native feature of DocumentDB and requires manual implementation.


I'm Abhay Singh, an Architect with 9 Years of It experience. AWS Certified Solutions Architect.

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