I ran across a wonky, albeit cosmetic, storage reporting error for Datastore Clusters on vSphere 5.x when using the vSphere Client (C#).
When reviewing a Datastore Cluster in the “Summary” tab under “Datastores and Datastore Clusters” it correctly reports a "Capacity." However, when viewing the “Hosts and Clusters” tab under “Datastores and Datastore Clusters” the vSphere Client will incorrectly reports how much has been "Allocated."
If you have a ESXi cluster of 5 ESXi hosts and the cluster has access to 3 x 1TB Datastores in a Datastore Cluster, the Summary tab under Datastores and Datastore Clusters will correctly report a Capacity of 3TB.
However, the Hosts and Clusters tab under Datastores and Datastore Clusters incorrectly reports that 15 TB of Allocated Space.
Basically, the Allocated Space incorrectly multiplies the size of the Datastore Cluster by the host factor.
Note however, that this DOES NOT appear in the vSphere Web Client as it only shows the correct Capacity.
Nor does it appear in does Get-DatastoreCluster <DatastoreClusteName> when using PowerCLI.