A new release of a business-critical application is to be hosted in a customer's home office location. Toreduce concerns regarding availability for the application, the customer will deploy a second…

A new release of a business-critical application is to be hosted in a customer's home office location. Toreduce concerns regarding availability for the application, the customer will deploy a second application instance into their Disaster Recovery (DR) location. If the home office location becomes unavailable the DR location will take over hosting the application. What is a mandatory requirement to allow take-over should disruption occur?