improper or incomplete firmware flash on a Cisco AF-6-UCS240-M7SX server, caused the storage controller to lose proper communication with the drives, and ESXi host reported an overall Skyline Health status of "Failed" with an operational health of "Unknown."
vSphere ESXI 8.0u3x
vSAN 8.0u3x
Because the firmware version was unlisted/unverified on the HCL and potentially applied incorrectly during the initial upgrade, the hardware entered a state where the ESXi host could no longer reliably communicate with the storage devices. This resulted in the capacity drives dropping offline and triggering the vSAN health failures.
A review of the Broadcom/VMware Hardware Compatibility List (HCL) for the Cisco AF-6-UCS240-M7SX revealed that the applied firmware bundle version—6.0(2.260044)—is not currently listed as a supported release. Cisco suggested a power drain of the server and re-installing the firmware.