Which statement about RAID reconstruction is true?

• A. Reconstruction requires hot spare disks.
• B. Reconstruction does not interrupt system services.
• C. Reconstruction can affect system performance.
• D. Reconstruction is always seamless with no performance degradation.

Answer: (C)

During RAID reconstruction, the system rebuilds data onto a replacement drive after a failure or when the array is degraded. This process is I/O-intensive because it reads data from the surviving disks and writes to the new disk. That extra read/write activity shares the system’s disk bandwidth with normal applications, which can increase latency and reduce overall throughput. Because of this competing workload, reconstruction can noticeably affect performance, especially on busy systems or with parity-based RAID levels that require more data to be read and recalculated. A hot spare is a common way to start rebuilding automatically, but it isn’t mandatory in every setup, and even with a spare, some degradation can occur during the rebuild. So the statement that reconstruction can affect system performance is the accurate one.