Amazon RDS Multi-AZ deployments enhance high availability and reliability for database instances by automatically replicating data to a standby instance in a different Availability Zone (AZ). In the event of a failure, AWS performs an automatic failover to the standby, minimizing downtime and ensuring business continuity. This setup is essential for mission-critical applications that require seamless database availability and disaster recovery.
Lets see how much does it take to perform Oracle RDS database failover? To find out, I created a small Oracle RDS database and tested failover with AWS CLI.
Here is how it was done.
1. Go to Aurora and RDS console (https://console.aws.amazon.com/rds) and click on Create database. Select Oracle, Amazon RDS, Oracle multitenant architecture, Multi-tenant configuration, Oracle Enterprise Edition. Select the latest RU(release Update) – Oracle 19.0.0.0.ru-2025-01.rur-2025-01.r2 I will name the database db1, container ODB1. ASs this will be a simple test, I took db.t3.small DB instance class (2 vCPU, 2GB RAM) and 50G allocates storage. Most of the preselected values on the create page can be left as they are, but be sure under Availability & durability/Multi-AZ deployment to select Create a standby instance – we do want standby to test the failover. Finally AWS tells me the estimated monthly costs – pretty affordable for a test which will took less than an hour. Click on Create Database and grab a coffee – it takes time 🙂 Finally my small database is ready. I am going to use one small EC2 instance(the same VPC as the database) to connect to the database. Lets see if the database is accessible – Yes, and the instance host is ip-10-10-0-198. Great! Now lets initiate failover. Select the database and under Actions, select Reboot. Reboot instance page appears. Make sure that ‘Reboot With Failover?’ is selected and click on Confirm.
The failover took less than 2 minutes and now host_name should be different – ip-10-10-1-20
In the next post i will check other Oracle HA possibilities in AWS as well will compare the downtime needed.
