# Aurora

## AWS Aurora

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* Aurora takes advantage of `RDS` features for management and administration.
* Aurora management operations typically involve entire clusters of database instances that are syncronized through replication.
  * The automatic clustering, replication and storage allocation make it simple and cost-effective to set up, operate and scale.
* *1/10th the cost of commercial database.*
  * You are only charged for the space that you use in an Aurora cluster volume.

## Aurora Data

Aurora data is stored in the `cluster volume`, which is a single, virtual volume that uses SSDs.

* A `cluster volume` consists of copies of the data across three AZs in a single Region.

**This data is automatically replicated.** Aurora also supports failover.

This architecture makes your data independent from the DB instances in the cluster.

* So you can delete an instance from the cluster and have 0 data loss.
* Aurora only erases the data if you delete the entire cluster.

**Also cluster volumes automatically grow as the amount of data increases.**

## Supported Engines

| MySQL      |
| ---------- |
| PostgreSQL |

## DB Instance Classes

Like RDS you can choose different instance classes for different needs.

## Basic Price Models

* You may choose a Serverless model, which automatically starts up or shutdown instances, and scales capacity up or down, based on needs. In this model you pay only for **capacity consumed**.
* You can choose Provisioned On-Demand instances and pay per **DB instance-hour.**
* You can also choose a Provisioned Reserved instances for additional savings.