A full interruption test is the most realistic and reliable way to ensure that recovery time objectives (RTOs) are met for an organization’s disaster recovery plan (DRP). RTOs are the maximum amount of time that a business can tolerate being offline after a disaster. A full interruption test involves shutting down the primary site and switching over to the backup site, simulating a real disaster scenario. This test can measure the actual time it takes to restore the systems, applications, and functions that are critical for the business continuity. A full interruption test can also reveal any issues or gaps in the DRP that might affect the recovery process.

The other options are not as effective as a full interruption test for ensuring RTOs are met. A cyber resilience test is a type of DR test that focuses on the ability to withstand and recover from cyberattacks. It does not necessarily cover other types of disasters or test the entire DRP. A tabletop test is a low-impact DR test that involves a walkthrough of the DRP with the key stakeholders and staff. It does not involve any actual switching over or testing of the backup systems. A parallel test is a type of DR test that involves running the backup systems alongside the primary systems, without disrupting the normal operations. It does not measure the time it takes to switch over or resume operations at the backup site.