The Storage Status section in vCenter Server shows a status of Unknown. For example:
This issue may originally occur with specific datastores, but may eventually affect all datastores.
Newly created datastores, show as unknown but while pre-existing datastores show as Normal.
Environment
VMware vCenter Server 8.0.x VMware vSphere ESXi 8.0 VMware vCenter Server 7.0.x VMware vSphere ESXi 7.0 VMware vCenter Server 6.0.x VMware vSphere ESXi 6.0
Resolution
The Storage Status is reported by the Datastore usage on disk alarm, which monitors datastore disk usage. This is a preconfigured alarm and it triggers automatically when problems are detected. This issue may occur if you have disabled the action for this alarm.
If you enable the Alarm, the proper alert status is visible. To enable the alarm:
Click the vCenter Server level at the top of vSphere Client Inventory.
When an object is selected in the Inventory, you can identify its disabled alarm actions:
In the General pane of the object's Summary tab.
In the Alarm Actions Disabled pane of the Alarms tab.
In the Alarm Actions column of the object's child object tabs. For example, if you select a host in the inventory, the Virtual Machines tab displays whether alarm actions are enabled or disabled for each virtual machine on the host.
The alarm for datastore disk usage is enabled at the datacenter level.