RDS

Relational Database Service (RDS)

What is Amazon Relational Database Service (Amazon RDS)? - Amazon Relational Database ServiceAmazon Relational Database Service

application architecture example

• Is a fully-managed database service that makes it easy to launch database servers in the AWS Cloud and scale them when required.

  • RDS will take care of updates or paching.

  • RDS will auto scale.

  • RDS will provide high availability automatically.

  • RDS will auto backup.

• Ideal for (OLTP - Online Transaction Processing), when you only gather specific data.

• Usually RDS uses EBS storage, and you can choose different types of EBS classes.

Supported Engines

MySQL
MariaDB
PostgreSQL
Microsoft SQL Server
Oracle Database
IBM Db2

DB Instance Classes

You can change your instance class, if your needs change.

This will determine the computation and memory capacity of a RDS instance.

Class	Description
db.m*	General purpose
db.z*, db.x*, db.r*	Memory optimized
db.c*	Compute optimized
db.t*	Burstable performance

The * represents the chosen generation, optional attribute and size.

Exemple:

db.m7g is a 7th-generation, general purpose instance powered by AWS Graviton3 processors.

Backups

• User initiated DB Snapshots of instance.

  • When instance is terminated, these backups are not deleted.

• Automated DB backups to S3.

  • Deleted by default when instance terminated.

  • Disabled by setting backup retention period to 0.

• Encryption of database and snapshots at rest available.

Deployment Strategies

Multi-AZ (Availability Zones)

Ideal for disaster recovery or availability. (Replication of data)

• When one of the instances fails, AWS does the failover to another instance automatically.

  • Route 53 will setup all that automatically.

• AWS automatically provisions and maintains one or more secondary standby DB instances in different AZ.

  • The primary instance is replicated to the other standby instances.

• Provides redundancy and failover support.

• It is possible to use the replicas to serve read traffic on Multi-AZ DB Cluster deployment only.

• Application should also be located in multiple AZ's.

• Available for all database types.

Read Replicas

• Ideal for performance.

  • The master instance focus on writes, and reads are designated to the replicas.

    • Multiple read replicas (up to 15 for Aurora).

  • When the master instance fails, one replica is promoted.

    • But data consistency is than lost.

    • And a new DNS for the replica.

• Supported for Aurora, PostgreSQL, MySQL and MariaDB.

• Cannot be put behind AWS ELB.

  • Use Aurora Cluster for automatic distribution of requests, software, Route 53 routing or HaProxy.