Failed to recommend placement of disks for machine ABCD on data store cluster. Fault code by DRS when making recommendations: storagePlacement. The DRS fault occurred when moving machines: vm-12345. Fault messages by DRS: The operation is not allowed in the current state of the datastore.
After confirming the compute cluster storage and the reservations, perform a manual clone of one of the VMs in the reservation pool.
We saw the below behavior:
Compatibilities Issues dialog:
The warning says: The operation is not allowed in the current state of the host.
(The host displayed is one in maintenance mode, and shouldn't count.)
If there are a lot of datastores, this may be a vCenter DRS bug where the host doesn't talk to DRS even though all is "well".