Like sharing disk, users can also attach direct LUNs to virtual machines in Red Hat Enterprise Virtualization, which allow for the same sharing as a normal disk image. The LUN from the SAN is connected to the hypervisor hosting the virtual machines via a host bus adapter of the host through which all the storage I/O takes place. A LUN is a number used to identify a logical unit related to computer storage. A logical unit is a device addressed by protocols and related to fiber channel, Small Computer System Interface (SCSI), Internet SCSI (iSCSI), and other comparable interfaces.
There are a few considerations that the end user has to keep in mind before using the direct LUN on virtual machines:
Direct LUN from the storage must be presented to all the hosts in the data center for the live migration of the virtual machine attached with direct LUN to work.
Exporting virtual machine direct LUN disk to RHEV export domain is not supported. Export of such virtual machines only...