https://kb.fortinet.com/kb/documentLink.do?externalID=FD46446#:~:text=On%20FortiAnalyzer%2FFortiManager%20devices%20that,to%20exchanging%20the%20hard%20disk.
If a hard disk on a FortiAnalyzer unit fails, it must be replaced. On FortiAnalyzer devices that support hardware RAID, the hard disk can be replaced while the unit is still running - known as hot swapping. On FortiAnalyzer units with software RAID, the device must be shutdown prior to exchanging the hard disk