Shared LUNs between ESxi hosts

Hi, I have a Unity 380 storage device available with me. I would like to  provision a LUN and share the same between two VMs residing in the 2 accompanying EsXI host servers.

As first step, i created the LUN and scanned it in the datatstore, the LUN comes up successfully but if i mount the LUN to any one host, it is not accessible to the other as no space on device left.

Can someone please guide what can be the process done here to achieve this?

Thanks in Advance

Kishan Shukla