Veeam ONE generates the “Storage connection failure” alarm during the backup jobs with storage integration activity.
During the backup job with storage integration activity, the storage snapshot is created as a logical unit on the storage device hardware level.
After the snapshot processing is finished, it is being deleted and the vCenter considers it as losing connection with the LUN which is actually the storage snapshot, but not the real storage device.
This causes the vCenter to register one of the following events, which are used to trigger the “Storage connection failure” alarm:
This is behaviour by design. It is recommended to suppress the alarm during the backup activity.
NOTE: See more details of how to suppress the alarms: https://helpcenter.veeam.com/docs/one/alarms/alarm_suppression_settings.html?ver=95