BICSI
RCDD · Question #279
RCDD Question #279: Real Exam Question with Answer & Explanation
The correct answer is C. N+2. N+2 redundancy adds exactly two spare units beyond the minimum required, allowing the system to tolerate two simultaneous failures without losing service.
Question
What type of redundancy provides two additional units, modules, paths, or systems in addition to the MINIMUM required to satisfy the base requirement.
Options
- AN
- BN+1
- CN+2
- D2N
- E2(N+1)
Explanation
N+2 redundancy adds exactly two spare units beyond the minimum required, allowing the system to tolerate two simultaneous failures without losing service.
Common mistakes.
- A. N represents exactly the minimum required with zero spare capacity, meaning any single failure results in a service interruption.
- B. N+1 adds only one additional unit beyond the minimum, tolerating only a single simultaneous failure rather than two.
- D. 2N is a fully mirrored configuration that doubles every component, which provides more redundancy than N+2 but is not defined as two additional units.
- E. 2(N+1) doubles the sum of the minimum plus one, representing a higher tier of redundancy than N+2 and is not the definition of two additional units.
Concept tested. Redundancy models N N+1 N+2 2N comparison
Reference. https://uptimeinstitute.com/resources/research-and-reports/tier-classifications-defined
Community Discussion
No community discussion yet for this question.