The primary purpose of regularly testing and updating a disaster recovery plan (DRP) is to ensure its continued adequacy and effectiveness. Organizations are dynamic; their technologies, business processes, personnel, and risk landscapes evolve. A plan that is not tested and updated can quickly become obsolete. Regular testing validates that the planned procedures, technical measures, and assigned responsibilities will function as intended during an actual disruption. This process identifies gaps, outdated information, and flawed assumptions, allowing the organization to remediate them and ensure the plan remains a viable tool for recovery. This aligns directly with the information security continuity principles in ISO/IEC 27001.

B. A disaster recovery plan is designed for significant disruptive events, not for the "registration of daily occurring faults," which falls under routine operational incident management.

C. While verifying backup availability is a critical part of DRP testing, it is only one component. The overall goal is to ensure the entire plan's adequacy, not just a single technical control for one team.

1. ISO/IEC 27001:2013, Information technology — Security techniques — Information security management systems — Requirements.

Reference: Annex A, Control A.17.1.3, "Verify, review and evaluate information security continuity."

Quote/Paraphrase: This control explicitly states that information security continuity controls should be "verified regularly in order to ensure that they are up to date and effective." This directly supports the need to test to ensure measures are adequate (effective).

2. ISO/IEC 22301:2019, Security and resilience — Business continuity management systems — Requirements.

Reference: Section 8.5, "Programme of exercising and testing."

Quote/Paraphrase: The standard specifies that an organization shall establish and implement a programme of exercising and testing to "validate the effectiveness of its business continuity strategies and solutions" and "evaluate business continuity capabilities." This process of validation and evaluation is precisely to ensure the plan is adequate.

3. Herbane, B. (2010). The evolution of business continuity management: A historical review of practices and drivers. Disaster Prevention and Management, 19(1), 43-56.

Reference: Page 51.

DOI: https://doi.org/10.1108/09653561011022159

Quote/Paraphrase: The publication emphasizes that testing and exercising are crucial to "validate the plan's viability" and "identify weaknesses before a real disaster strikes." This validation process is fundamental to confirming that the planned measures are adequate.