Hyper-V R3 Storage Improvements

Windows Server 8 brings with it Hyper-V R3.  Within R3 there are quite a few new features and two specific to storage that I know a lot of people are looking forward too.  The first one I have been asked about hundreds of times and it is finally available in Windows 8 Hyper-V, virtual fibre channel HBAs.  You can now connect a Hyper-V R3 virtual machine to a fibre channel SAN.

The virtual FC HBA does have a few requirements:

• A server running Windows Server 8 with Hyper-V role installed.
• The server requires a Fibre Channel host bus adapters (HBAs) with a driver that supports Virtual Fibre Channel. 
• A virtual machine configured to use a virtual Fibre Channel adapter
• The VM OS must be Windows 2008, 2008 R2 or Windows Server 8
• Note you cannot boot from a virtual FC LUN

Windows Server 8 also brings a new disk type to Hyper-V R3, a VHDX.  Currently a VHD file is limited to 2040GB in size.  This is great for most workloads but in larger environments it can pose a challenge.  VHDX solves this by boosting the size of a VHDX file to a maximum 16TB (yes Terra).  Also of note is that Dynamically Expanding disks are now the recommended option.

In addition to this VHDX also changes the metadata structure in an effort to reduce data corruption.  VHDX also offers

• Larger block sizes for dynamic and differential disks.
• 4-KB logical sector virtual disk
• The ability to add custom metadata about the VHDX file
• Trim which allows the physical storage device to reclaim any unused space

It should be noted that only Windows Server 8 (host and VM) supports the VHDX file format at this time.