One of the highly anticipated features of Windows Server 8 is the ability to provide individual Hyper-V virtual machines with virtual fibre channel HBAs. This feature is new to Hyper-V with the 3rd release of the Microsoft virtualization platform.
A virtual fibre channel port is useful to allow a virtual machine direct access to the storage resource. This can be to ensure zoning is met, such as which worldwide names (WWNs) can access a specific LUNs on a storage resource. Further, this can be e an enabling step for virtualization to ensure this zoning is maintained while also consolidating costly fibre channel port assignments. The virtual fibre channel port leverages the standard N_port ID virtualization (NPIV) process to address virtual machine WWN’s within the Hyper-V host’s physical HBA.
In my vSphere virtualization practice, I’ve come across this as the fibre channel NPIV virtual WWN; which effectively leverages the same NPIV standard. With Hyper-V the decision processes are the same: basically leverage the native virtual disk format (VHD, VMDK, VHDX, etc.) unless specific requirements of a virtual machine exist.
This can lead to a number of efficiencies and options with the virtual machine. Primarily, if the virtual machine’s inventory (VHD, VMDK, VHDX, etc.) contains the entire data profile, features such as snapshots and checkpoints can be leveraged. If virtual fibre channel interfaces are assigned; then that data is not part of the virtual machine in that sense. Back to the earlier point of focusing on the requirements, only provision fibre channel NPIV or virtual fibre channel if the VM needs a LUN directly. Figure A below shows this feature in both Hyper-V and vSphere:
Both Hyper-V and vSphere virtual HBAs shown
Historically, limitations of the size of a virtual disk file may have been a good reason to provision storage this way. With the expanded capacity of the VHDX file format (16 TB), those reasons may soon be evaporating.
Do you see a use case for virtual fibre channel with Hyper-V and Windows Server 8? Share your comments below.