Unmounting a VMFS datastore
It is recommended to unmount a VMFS datastore before the LUN that is backing it is un-presented from an ESXi host.
It is advised that you take care of the following before you proceed with the unmount operation:
All the VMs should be migrated off to a different datastore
The datastore should be removed from a datastore cluster
The datastore should remain unmanaged by SDRS (Storage DRS)
SIOC (Storage I/O Control) should be disabled for the datastore
The datastore should not be in use as a vSphere HA Heartbeat datastore.
How to do it...
A VMFS volume can be unmounted from the vSphere Web Client GUI or by using esxcli at the ESXi console.
Using the vSphere Web Client GUI to unmount
vSphere Web Client can be used to unmount a datastore. It is particularly useful when you have to unmount the datastore from multiple ESXi hosts.
The following steps will guide you through the process of unmounting a VMFS datastore using the vSphere Web Client:
Use the vSphere Web Client to connect...