Windows Server 8: Hyper-V Ready for the Big Time

IT shops, large and small, will find a lot to like in Microsoft's latest version of Hyper-V.

At this week’s BUILD Conference in Anaheim, Calif., Microsoft released additional information on Windows Server “8,” the follow-up server operating system to Windows Server 2008 R2. While Microsoft claimed that hundreds of additional features would be built into the flagship corporate operating system, the biggest changes seem to be related to Hyper-V.

Let’s take a look at some of the new storage, network, performance and disaster recovery enhancements to Microsoft’s third-generation hypervisor.

Hyper-V Storage

On the storage side, Microsoft added virtual fiber channel (FC) for Hyper-V virtual guests.  Virtualized Windows Server clusters can connect to other SAN fabrics via the physical host bus adapters (HBAs) on the host.  You can have up to four virtual HBAs per VM, with each adapter assigned its own worldwide name (WWN).

Virtual machine migration also gets a boost in the new Windows version.

Live Migration is now available for non-clustered Hyper-V servers.  This alone is a great feature as it opens the door for organizations that lack the financial resources to buy, build and manage a storage infrastructure for their VMs. 

With prior versions of Live Migration, you could only move VMs that resided on the same Cluster Shared Volume (CSV).  Now, moving a Hyper-V VM from one server to another doesn’t require shared disk.  You can simply move a VM from Server A’s local storage to Server B’s local storage without any downtime.   And, to top that off, Hyper-V does away with the limitation on the maximum number of VMs that can simultaneously live-migrate between servers. 

The original limit of migrating VMs was around half the number of Hyper-V hosts in your cluster.  The new maximum, according to Microsoft, is based on the quality and configuration of the hardware you’re running.  No specific numbers were given, however one can assume that the number of Live Migrations will be impressive with the right equipment.

Quick Storage Migration is now Live Storage Migration.  Somewhat similar to Live Migration, Live Storage Migration moves virtual machine virtual disks between different types of storage with a minimal amount of interruption.   This feature will come in handy when a virtual machine repository starts to run low on disk space.  The virtual machine administrator would simply move the virtual machine disks to a storage device with ample space.  A Live Storage Migration can happen between any combination of NAS, SAN or DAS devices.

Somewhat related to storage, Microsoft also introduced a couple of other features related to the virtual machine disk file.  Live VHD Merge lets administrators consolidate a virtual machine’s snapshots while the VM is running.

 Also introduced in version 3 of Hyper-V is the VHDX format.  This is a new additional disk file format that provides larger block sizes that bump the upper disk limit for a VHDX file to 16TB in size, well over the 2TB limit of a standard VHD file.