One of the least-known features introduced in vSphere 4.x that continues to be in vSphere 5 is VMDirectPath I/O. In this chapter, I explain what it is, how it works, and some practical design implementations.
Have you ever wanted to access a certain storage device directly from within a Virtual Machine (VM) but the devices is not Raw Device Mapping (RDM) capable?
Do you have a fibre-attached tape library that you want to use within a VM and provide multipathing to it?
Do you have an application that requires a specific Peripheral Component Interconnect (PCI) device accessed directly from within the VM?
The answer to these questions is a definite yes! (With caveats.)
VMDirectPath on vSphere ...