Redundancy in Business Continuity and Disaster Recovery
Key Takeaways
Subdomain 2.2 is titled Understand redundancy and lists BC and DR.
Redundancy means a second way to keep a function running if the first fails.
A redundant design is only useful if the two paths do not fail for the same reason.
Source: ISC2 CC Exam Outline effective September 1, 2026, subdomain 2.2, checked 2026-10-22.
Redundancy and the Outline
Subdomain 2.2 is titled Understand redundancy and covers Business Continuity (BC) and Disaster Recovery (DR). Redundancy means a second path or resource that keeps a function running when the first one fails. The outline does not name specific facility or network designs, so use the concept, not a list of devices.
Source: ISC2 CC Exam Outline effective September 1, 2026 (v01/2026), subdomain 2.2, https://www.isc2.org/certifications/cc/cc-certification-exam-outline, checked 2026-10-22.
Common-Cause Failure
Two redundant paths that depend on the same power source, network path, or location may fail together. In a scenario, ask whether the second path fails for a different reason from the first. A redundancy that shares the same failure cause does not protect the function against that cause.
What the Outline Lists for This Section
The outline names these items. Be able to explain each one in plain language and apply it to a short scenario:
- 2.2: Business Continuity (BC)
- 2.2: Disaster Recovery (DR)
Common Traps
A common trap is treating business continuity and disaster recovery as the same plan. Continuity keeps the business running; disaster recovery restores technology. Match the answer to the part the scenario describes.
Why can two redundant systems still fail together?
They depend on the same failure cause, such as one shared path
They have different vendors, so a single vendor patch cannot reach both systems at the same time
They run different operating systems, so a flaw in one operating system cannot affect the other system
They each have a separate backup generator, so a single power loss cannot affect either of them at all
A redundancy answer should name what the second path is and whether it can fail for the same cause as the first, since a shared cause defeats the redundancy.
Sections you finish are checked off in the contents.