Overview

• RDS stands for Relational Database Service.
• It’s a managed DB service for DB use SQL as a query language.
• It allows you to create below databases in the cloud that are managed by AWS

     * Postgres
     * MySQL
     * MariaDB
     * Oracle
     * Microsoft SQL Server
     * Aurora (AWS DB)
  

Note: Using RDS we cannot SSH into EC2 instances

Advantage of Using AWS RDS over provisioning DB on EC2 instances

• We can automate Provisioning and OS patching
• We can take backups continuously and restore it to a specific time
• We can improve scaling capability (vertical and horizontal)
• The storage is backed by EBS - gp2 or iol
• Monitoring dashboards
• Read replicas for improved read performance
• Multi AZ setup for DR (Disaster Recovery)
• we can setup maintenance windows for upgrades

RDS Backup

Backups are automatically enabled.

RDS AutoScaling

• RDS helps to increase DB instance storage dynamically.
• RDS detects and scales automatically if the DB instance storage is low.
• Useful for applications with unpredictable workloads and it supports all RDS DB engines (Maria DB, SQL Server, Oracle, My SQL, PostgreSQL).

RDS Read Replicas

• Supports up to 5 Read replicas
• Replication between master to slave is ASYNC so that the replication is consistent
• Read replicas can be promoted to their primary DB
• In order to use read replica, applications must use read replica connection string. RDS N/w Costs:

RDS Multi AZ - Disaster Recovery

• Replications are SYNC
• Increase availability
• One DNS name - automatic app failover to standby
• Failover in case of loss of AZ, loss of network, instance or storage failure
• No manual intervention in apps
• Not used for scaling
• Multi-AZ replication is free
• The Read Replicas be setup as Multi AZ for Disaster Recovery (DR)

RDS Security Encryption