Before you begin, make sure that the following steps have been performed:

• Migrate all the VMs on the datastore that you intend to unmount to another datastore.
• The datastore should be removed from a datastore cluster.
• The datastore should remain unmanaged by Storage DRS (SDRS).
• The Storage I/O Control (SIOC) should be disabled for the datastore.
• The datastore should not be in use as a vSphere High Availability (HA) heartbeat datastore.
• Make a note of the NAA ID of the storage device backing the VMFS datastore. This can be done by selecting the datastore and navigating to Configure | Device backing:

• Alternatively, you can run the esxcli storage vmfs extent list command to see the following list: 

Regardless of the method used, it is important to unmount the VMFS volume from all the hosts before you detach the storage device and unpresent the LUN.