According to the official FortiAnalyzer documentation, for models that utilize software RAID, the recommended and required procedure for replacing a failed hard disk is to first power off the unit. This ensures the system's integrity and allows the software RAID controller to properly recognize the new disk upon reboot and initiate the rebuild process safely. Attempting to replace a disk while the system is running (hot-swapping) is not supported for software RAID configurations and is reserved for specific models equipped with hardware RAID controllers.

B: Downgrading and then upgrading the RAID level is not a standard or documented procedure for disk replacement. This action is unnecessarily complex and carries a high risk of data loss.

C: Clearing alarms before resolving the underlying physical fault is incorrect practice. Furthermore, replacing the disk while the FortiAnalyzer is running is not supported for software RAID.

D: A hot swap is the process of replacing a component while the system is operational. This capability is explicitly supported on FortiAnalyzer models with hardware RAID, not software RAID.

1. FortiAnalyzer Administration Guide 7.4.1

"System Settings" > "RAID Management" > "Replacing a failed disk".

The documentation states: "If a hard disk in the RAID array fails

you must replace it. For FortiAnalyzer models that support software RAID

you must power off the device before replacing the failed disk. For FortiAnalyzer models that support hardware RAID

you can hot-swap the failed disk without powering off the device." This directly confirms that shutting down is the correct procedure for software RAID.