Databases
AWS has many different types of database offerings.
RDS
Relational Database Service offers managed DB services for different SQL flavors. This means they have automated provisioning and patching, continuous backups, multi-AZ setup for disaster recovery, and more. You can create read replicas of your DB in multiple AZs for faster read times around the world. There are also multi-AZ deployments for failover, where you read/write to the main DB until it fails.
Amazon Aurora
Cloud-optimized Postgres or MySQL database that has much better performance over normal RDS. Storage automatically grows based on usage. Costs more than RDS but is more efficient. There is also a serverless offering that auto-scales based on load and you pay per second. Good for infrequent or unpredictable workloads.
ElastiCache
Managed Redis or Memcached service with in-memory databases for high performance and low latency.
DynamoDB
Fully managed NoSQL database from AWS. Uses a serverless model for scaling and has a very low latency retrieval. Data is defined with a partition key and sort key which make up the primary key. DAX, or DynamoDB Accelerator, is an in-memory cache for DynamoDB with significant performance improvements. Global Tables can be used to replicate data to multiple regions and allow multi-region reads and writes.
Redshift
Based on Postgres, but used for data processing, or OLAP (online analytical processing). Think analytics and data warehousing. You load data once an hour and it scales better for many PBs of data. This also has a serverless offering for less frequent workloads.
EMR
Elastic MapReduce is used for creating Hadoop clusters for Big Data.
Athena
Serverless services to query data in S3 with SQL. Supports CSV, JSON, and other file formats. You pay $5 per TB scanned.
QuickSight
ML powered dashboard for visualizing your data.
DocumentDB
AWS implementation of MongoDB. Fully managed with replication across 3 AZ.
Neptune
Fully managed graph database.
Timestream
Fully managed time series databse.
QLDB
Quantum Ledger Database is a ledger type database for recording financial transactions. It is immutable like the blockchain, but it is hosted by AWS.
Amazon Managed Blockchain
This helps you build applications on the blockchain and make it decentralized. It supports Hyperledger Fabric and Ethereum.
AWS Glue
Managed ETL (extract, transform, load) service to prepare data for analytics. Can be used to load data into Athena, Redshift, or EMR.
Database Migration Service
Helps you transfer data from one database (on-prem) to another in AWS. It allows the source database to operate while the migration is taking place.