When a datastore is placed in maintenance mode, if the datastore hosts vCLS VMs, you must manually storage vMotion the vCLS VMs to a new location or put the cluster in retreat mode.
- Login to the vSphere Client.
- Navigate to the cluster on which vCLS must be disabled.
- Copy the cluster domain ID from the URL of the browser. It should be similar to domain-c(number).
- Navigate to the vCenter Server Configure tab.
- Under Advanced Settings, click the Edit Settings button.
- Add a new entry config.vcls.clusters.domain-c(number).enabled. Use the domain ID copied in step 3.
- Set the Value to False.
- Click Save.
vSphere HA does not perform optimal placement during a host failure scenario. HA depends on DRS for placement recommendations. HA will still power on the VMs but these VMs might be powered on in a less optimal host.
To remove Retreat Mode from the cluster, change the value in step 7 to True.