Where AWS Stores Your Data

When Aisha's team needed to store customer support transcripts, the decision took a week. They argued between S3 (cheap and simple), DynamoDB (queryable), RDS (familiar), and ElastiCache (fast). They ended up using all four. They were not wrong.

This course is about the choices behind that decision. AWS gives you many ways to store data, and the right answer depends on access patterns, durability needs, query complexity, and cost. Picking wrong is one of the most expensive mistakes a cloud developer can make — both literally on the bill and figuratively in the rewrite three months later.

What This Course Covers

Across 16 chapters, you will learn the four pillars of AWS data services:

• Amazon S3 — object storage. The most-used AWS service, period. The default home for files, backups, static assets, data lake content, and almost everything else that does not need to be queried row by row;
• Amazon DynamoDB — serverless NoSQL. AWS's flagship key-value and document database. Fast, scales to anything, but only if you model your data the right way;
• Amazon RDS and Amazon Aurora — managed relational databases. PostgreSQL, MySQL, MariaDB, Oracle, SQL Server. Aurora is AWS's higher-performance, cloud-native take;
• Amazon ElastiCache and DynamoDB Accelerator (DAX) — caching layers. Redis and Memcached for general caching; DAX for sub-millisecond reads in front of DynamoDB.

How to Choose, in One Pass

A first-pass decision tree most developers can lean on:

• Need to store files, images, logs, or large blobs? → S3;
• Need a queryable database with predictable access patterns at any scale? → DynamoDB;
• Need SQL, joins, transactions across multiple tables? → RDS or Aurora;
• Need to make any of the above faster for hot data? → ElastiCache or DAX. We will spend the rest of the course on the nuances — because the first pass is wrong about a third of the time.

A Note on the DVA-C02 Exam

This course covers a heavy chunk of the exam. Storage and database services account for roughly 25% of DVA-C02 questions. Pay extra attention to:

• S3 storage classes and lifecycle rules;
• DynamoDB partition key design;
• DynamoDB Streams and triggers;
• RDS vs Aurora differences;
• When to add a cache. Let's start with the service that anchors everything else.