Detaching an active RDM LUN device doesn't show its being used

[arifr]

I am on ESXI 5.1 environment using HPE 3PAR SAN Storage for Datastores and RDM disks. When detaching an RDM LUN storage device from HOST->Configuration->Storage, all three checks are green-ticked (Ok), one of them which is "The device is not used by VM as an RDM disk" should be red, because the LUN is being used by a VM. However its working fine when I am trying to detach a device which is an active Datastore, then its showing red for "The device is not used by a datastore" check - which is perfectly fine. Not sure what is going on. Without the checks not working fine, its risky to detach/remove a storage device. Anyone has any idea how to make it work?

Also in case this doesn't work, any other way to find out if the device is not being used and safely detach it? Appreciate your response.

[SupreetK]

Are you sure the RDM LUN is actively being reserved by the VM? Is the VM in powered on state or powered off?

Cheers,

Supreet

[arifr]

My bad. I just found out that it was a different Host than the VM's Host I was trying to detach the LUNs- and off course it wont give prompt. When I tried from VM's Host, I got message correctly.

Thanks for your reply anyway.