The compiled client’s data and motivations, together with our reasonings, led us to design and implement the following architecture in AWS.
For the Fusion Middleware Application Server, a single instance was used in an Auto Scaling group across several AWS availability zones. The Auto Scalation group will always ensure that there is at least one instance up and running, in whatever area of availability, achieving compliance with the proposed RTO. Moreover, applications access to that instance through an ELB (Elastic Load Balancer) for which an alias was created in Route53 to facilitate access to it through a custom URL.
Elastic File System (EFS) was used to create the shared directories, file sharing through the nfs v.4 protocol in different availability zones simultaneously, without having to have an additional host and paying only for the used storage.
For the Oracle database instance, the AWS RDS service was used with the BYOL (Bring-Your-Own-License) licensing model and in multiple Availability Zones, satisfying also with the RTO and reducing to a minimum the maintenance tasks, backup management, performance monitoring, and so on.
Finally, in order to make EFS backup copies, the AWS Data Pipeline service was used, which makes a daily copy with 7 days’ retention, as well as a fortnight copy with a 2-month retention.