Interview Q&A / AWS & Cloud

1. What is the difference between RDS and DynamoDB, and when would you use each?

   RDS is a managed relational database service running engines like MySQL or PostgreSQL, with SQL, joins and transactions. DynamoDB is a serverless key-value and document database that gives fast, predictable performance at very large scale if you design around known access patterns. Use RDS for relational data and flexible queries; use DynamoDB for simple, high-volume lookups by key.

   IntermediateIn-depth4 min read
2. What is the difference between RDS Multi-AZ and a read replica?

   Multi-AZ keeps a synchronous standby copy in another AZ for automatic failover, improving availability. A read replica is an asynchronous copy that serves read traffic to scale performance and can be promoted if needed.

   BeginnerQuick answer1 min read
3. How is Amazon Aurora different from a standard RDS database?

   Aurora is AWS's cloud-built MySQL- and PostgreSQL-compatible database. It stores data in a shared cluster volume copied six ways across three AZs, supports up to 15 low-lag replicas, and fails over faster than standard RDS.

   IntermediateQuick answer1 min read
4. What is the difference between RDS automated backups and manual snapshots?

   Automated backups are taken daily with transaction logs, support point-in-time restore within a retention period of up to 35 days, and are removed with the instance. Manual snapshots are taken on demand and stay until you delete them.

   IntermediateQuick answer1 min read
5. What is RDS Proxy and why would you use it with Lambda?

   RDS Proxy sits between your application and the database and pools connections. It stops many short-lived Lambda functions from opening thousands of connections that exhaust the database, and it speeds up failover handling.

   AdvancedQuick answer1 min read