To unpresent a LUN from an ESXi 5.0 host using vSphere Client:
When the device is detached, it stays in an unmounted state even if the device is represented (that is, the detached state is persistent). To bring the device back online, the device needs to be attached.
If the device is to be permanently decommissioned from an ESXi servers(s) , you may have to manually remove the NAA entries from the host configuration by issuing these commands:
To unpresent a LUN from an ESXi 5.0 host from the command line: