In the vSphere Web Client, an alarm is triggered when vCenter Server detects that a workload from a host might be affecting performance.

The alarm Unmanaged workload is detected on the datastore is triggered.

The array is shared with non-vSphere workloads, or the array is performing system tasks such as replication.

There is no solution. vCenter Server does not reduce the total amount of I/O sent to the array, but continues to enforce shares.