Cloud IaaS (Infrastructure as a Service) is a service model that allows users to rent virtualized computing resources over the internet, such as servers, storage, network, and software. Cloud IaaS can provide several benefits for disaster recovery and failover scenarios, such as:

Lower cost: Cloud IaaS can reduce the capital and operational expenses of building and maintaining a physical disaster recovery site, asusers only pay for the resources they use on demand12.

Scalability: Cloud IaaS can offer flexible and elastic scalability of resources, as users can easily provision or deprovision resources according to their needs and workload12.

Availability: Cloud IaaS can ensure high availability and reliability of the application, as users can leverage the cloud provider’s redundant andgeographically distributed infrastructure12.

Simplicity:Cloud IaaS can simplify the failover process, as users can use the cloud provider’s tools and services to automate and orchestrate the failover operations12.

Therefore, building a cloud IaaS and performing a failover of the application would be the most cost-effective solution for the company, as it would allow them to simulate a failover of a critical application on production configurations and IP address schemes without investing in a physical disaster recovery site.