Single-AZ vs Multi-AZ Deployment in AWS RDS

• Single-AZ Deployment
  • Overview: RDS will be created in any one AZ in db subnet group
    
  • No Failover: If the database fails we have rely on our backups to create a new database
  • Recommended for dev/test environments
  • To make it work for production, backup strategies have to be decent
• Multi – AZ Deployment
  • Overview:
    • RDS will create a Main and Stand by DB instance in two different AZ
    • Any changes in main will be synced to Standby (i.e. a DB statement will be complete only when it is synced with Standby)
  • Automatic Failover between Master adn Standby is available
  • Master and Standby will be of same size
  • RDS Endpoint is a DNS Name which points to master and if failover happens it points to standby
    
  • Recommeded for running Production instances
• Read Replicas can be created in same region or cross region. Read Replicas help in unloading the main db instance with read traffic.
  

Creating a Read Replica

• Create a free tier mysql rds instance
• Ensure Backups are enabled
• Create read replica