Dynamo DB 

Is a fast and flexible NoSQL DB for applications that need consistent single-digit millisecond intently at any scale. It is a fully managed database and supports both document and key value data models.

Dynamo DB Characteristics

1. Stored on SSD
2. Spread Across 3 geographically distinct data centers
3. Eventual read consistency by default
4. Strongly consistent reads

Eventual Consistent Reads: Consistency across all copies of data is usually reached within a second. Performing a read after a short duration should return updated data.

Strongly Consistent Reads: A strongly consistent read returns as a result that reflects all writes that received a successful response prior to that read.

Dynamo DS pricing:

• Write through put $0.0065 per hour for every 10 units.
• Read throughput $0.0065 per hour for every 50 units.
• Storage cost of $0.25 GB per month 

DynamoDB Data Model 

Simple DynamoDB Architecture