A lot of sensors are reported with the unknown state under the Host Hardware Sensor Status Changed alarm.
In version 6.5 Veeam ONE is using CIM-XML over MOB to monitor hardware status.
Prior to v6.5, some hardware sensors did not return the correct status due to a known VMware issue - when host's sensors display wrong status via vCenter Server's Managed Objects Browser (MOB). In v6.5 a more accurate hardware monitoring protocol CIM-XML is used, which completely eliminates such behavior. Be aware that vSphere Client uses the same protocol to obtain sensors' states.
Moreover, starting with Veeam ONE v6.5 the hardware monitoring became more granular, and you may notice way more sensors available in v6.5 compared to v6.0. But for some sensors, VMware does not have any state and returns the 'unknown' status. Please keep in mind that the correct state for 'well-known sensors' is always available via CIM-XML (which is utilized by Veeam ONE by default).
The alarm may or may not be triggered depending on the deployment scenarios of Veeam ONE 6.5. If you have fulfilled an upgrade from 6.0 to 6.5, the alarm will be triggered.
If you have fulfilled a fresh installation of 6.5, the alarm will not be triggered, although some of the sensors may be reported with the 'unknown' state on the Hardware tab.
The actual state of error and warning, however, should trigger the alarm as expected.
Be sure to compare sensors' state in Veeam ONE and on hosts' Hardware Status tab in vCenter Client, as well as to check the VMware rollup state in vCenter and host MOB as described in KB1007.
Please be aware that we’re making changes which will restrict access to product updates for users without an active contract.