No vSAN Shutdown button/option visible in the vCenter UI for hosts running ESX versions prior to 7.0 U3 (even with vCenter is running version 7.0 U3 or higher).
***PLEASE NOTE*** This should not be confused with the "Turn Off vSAN" option available in the Cluster Configuration Tab, under vSAN->Services.
"Turn Off vSAN" is not to be used to shut down a vSAN cluster.
ESX 7.0U1
ESX7.0U2
There is no automated workflow in the vSphere UI for vSAN Cluster Shutdown for hosts running ESX versions prior to 7.0U3 and a manual shutdown process should be followed.
Please proceed to the below document for the complete process and vSAN Shutdown prerequisites and steps: