Move vSphere Cluster Services (vCLS) VMs datastore
You will definitly face this issue if you enable HA or DRS on a cluster. The vSphere Cluster Services (vCLS) VMs are created per host on a randomly datastore. Pretty sure you are not happy with the selection and want to change it. If you try to change the datastore by Storage vMotion you will get this error which tries to prevent you from doing it. I will show you a much better (and supported) way of doing it.
vCLS is a new feature launched with vSphere 7 Update 1. In this new feature, vCLS ensures cluster services such as vSphere DRS and vSphere HA are all available to maintain the resources and health of the workloads running in the clusters independent of the vCenter Server instance availability.
Since it is a relatively new feature, it is still being improved in the latest versions, and more options to handel these VMs are added. For example, you are able to set the datastores where vCLS can run and should run. This option was added in vSphere 7 Update 3.
Move vCLS datastore
The tasks is performed at cluster level. Go to the Cluster, then Configure tab, then select the section vSphere Cluster Services and Datastores.
Here you have two options, datastores where vCLS are allowed to run and datastores where vCLS are not allowed to run. In this case, we will only move the vCLS VMs to run in a particular datastore (for security, you should add a second datastore if the first one is not available).
Select your Datastores and click Add.
As soon as you select add, the job has already been done. Some magic will no happen.
The vCLS VMs will automatically move to the datastores you selected.
The datastore move of vCLS is done.