I was completing tasks to delete datastores and consolidate storage capacity but hit a blocker when attempting to put a datastore in to Maintenance Mode. The datastore didn’t go in to Maintenance Mode and I was left with a few vSphere Cluster Services (vCLS) VM’s unable to move.
If you’re unsure what these vCLS VM’s are, I really recommend reading Duncan Eppings blog post HERE which containts everything you need to know.
Manually Storage vMotioning the vSphere Cluster Services (vCLS) VM’s failed and gave an error A specified parameter was not correct. StoragePlacementSpec.vm. Here is a simple fix and what I did to configure the cluster so the vCLS VMs resided on different datastore which allowed me to successfully decommission the datastore they were unable to move from.
You can see here, the vCLS VMs are the only VM’s remanining on the selected datastore.

Attempting the manully migrate the vCLS VMs with a Storage vMotion resulted in this error:

Select the required Host Cluster in your inventory > Select Configure > Navigate to the vSphere Cluster Services > Select Datastores > Click Add

Choose a suitable Datastore for the vCLS VM’s to reside > Click Add. Note: You may select more than one datastore here but I’m just using this configuratioin to empty the datastore I want to delete and will remove this setting again after

You’ll now see the selected datastore in the vCLS Allowed window and the vCLS VM’s will now proceed to adhere to this configuration by running on the allowed datastore.

The Task Console shows the activity from the vCLS VM’s after applying this setting…

…and the datastore which previously had the stuck vCLS VM’s is now empty and ready to put in to Maintenance Mode before further datastore decommission steps.

To keep the default confiuration and in the interest of allowing vSphere to manage these vSphere Cluster Services, I then removed the datastore from the vCLS Allowed configuration again.
Select Host Cluster in your inventory again > Select Configure > Navigate to the vSphere Cluster Services > Select Datastores > select the datastore you added in the previous steps > Click Remove

There is information to confirm that removing all datastores will revert back to default configuration > Click Remove
