AWS Database Services: RDS, DynamoDB, ElastiCache, Neptune and Redshift

AWS provides following services under database section:

1. RDS

2. DynamoDB
3. ElastiCache

4. Neptune

5. Redshift

Following are some basic and important points about AWS Database services:

RDS

1. Relational Database Service. Supports Aurora, MySQL, MariaDB, PostgreSQL, Oracle, MS SQL Server.

2. Backup and Restore methods: Automated (done by AWS automatically, backs up data with transaction logs) and Snapshots (manual process, usually done by system admins).

3. To improve DB performance, you can use ElastiCache, DAX and Read Replicas.

Aurora 

1. Combination of MySQL and PostgreSQL (RDBMS based).

2. Up to 5 times faster than standard MySQL databases and 3 times faster than standard PostgreSQL databases.

3. Automatically scales up to 64TB on SSD per database instance.

4. Replicates 6 copies of database across 3 Availability Zones.

5. Each DB cluster can have up to 15 READ replicas.

6. Failover takes less than 30 seconds.

7. Backs up database to S3.

8. You can monitor database performance using Amazon CloudWatch.

DynamoDB

1. DynamoDB (Dynamo Database or DDB) is Amazon NoSQL Database.

2. DynamoDB Security is provided by Fine-Grained Access Control (FGAC) mechanism. FGAC is based on the AWS IAM.

3. DynamoDB Triggers integrate with AWS Lambda.

4. DynamoDB Streams provides a 24-hour chronological sequence of updates to items in a table. AWS Lambda can read updates to a table from a stream.

5. Dynamo DB Accelerator (DAX) is in-memory database cache for Dynamo DB.

Neptune

1. Graph based database

Redshift 

1. Data Warehouse and Reporting System in the Amazon Cloud.

2. Use OLAP (Online Analytical Processing), SQL and BI tools to analyze the data.

3. Redshift Spectrum extends the power of Redshift to query unstructured data in S3 (without loading your data into Redshift).

ElastiCache

1. In-memory database cache in the Amazon Cloud for fast performance.

2. ElastiCache Engines: Redis, Memcached

DMS

1. Database Migration Service with zero/negligible downtime.

2. Supports homogenous (example: Oracle to Oracle) and heterogeneous (example: Oracle to Aurora or MySQL) database migration.