During the initial phase of adding shared storage to an ESXi host, LUN devices are presented to the ESXi host. The presentation is achieved at the storage and fabric levels. We will not get into the details of how a LUN is presented using the storage or fabric management software as that is beyond the scope of this book.
Once the LUNs are made available to the ESXi hosts, you can then format them with VMFS to host the virtual machine files. The LUNs can also be presented as RAW volumes to the virtual machines, in which case they are called Raw Device Mappings (RDMs). For more information on RDMs, refer to the recipe Attaching RDM to a virtual machine in Chapter 11, Creating and Managing Virtual Machines.
In this recipe, we will learn how to view the LUNs that are already presented to an ESXi host.
