An organization wants its critical service to keep operating if one server fails. Which control most directly addresses this requirement?

### Why this is right Redundancy means providing duplicate critical components. If one server fails, another component can take over, reducing the chance that the service becomes unavailable. ### The concept Availability is the ability of authorized users to reach usable information and services when needed. Redundancy supports availability by avoiding reliance on a single component. It can be combined with fault-tolerant design and workload distribution, depending on the service's requirements. Redundancy does not mean a system can never fail; it means a failure of one component is less likely to stop the entire service. ### The other options - **B. Multifactor authentication**: This helps verify a user's identity and can support confidentiality, but it does not provide a replacement server. - **C. Hashing**: A hash can help detect whether data has changed. It does not keep a service operating after a server failure. - **D. Need-to-know access**: This limits access to what users need for their work, helping protect confidentiality and integrity rather than service continuity. ### Terms - **Redundancy**: Duplicate components that can take over when a primary component fails. - **Availability**: The ability of authorized users to access usable services when needed. - **Multifactor authentication**: Authentication requiring evidence from more than one factor. - **Hash**: A compact value calculated from data and used in part to detect changes. - **Need-to-know access**: Giving users access only to resources required for assigned duties. ### Remember If the requirement is continued service after a component failure, look for redundancy or fault tolerance.