正解:
The degraded status on Server 2 indicates a RAID-5 issue, typically due to a failed or failing drive. In RAID-5 configurations, when one drive fails, the system can still operate but with reduced performance as parity data is used to rebuild missing data on-the-fly.
Recommended Replacement Drive:
- To minimize performance degradation, the replacement drive should be:
- SAS HDD with the same specifications (64KB stripe size, no read-ahead, and write-back policy).
- Matching the configuration exactly ensures seamless integration and optimizes recovery speed in the RAID-5 array.
In RAID-5, degraded performance is expected when one drive fails, as parity data needs to rebuild missing information during each read/write process. Replacing the failed drive restores the RAID array to optimal status, reducing the load on existing drives and returning the system to normal read/write performance. The write-back policy and disabled disk cache settings are designed to reduce latency and increase efficiency, essential for handling real-time applications.