Enhancements to Hyper-V in Windows Server 2008 R2

The release of Windows Server 2008 R2 Hyper-V is eagerly anticipated, due in large part to the many excellent new features coming with this release.  The following information provides an overview of the feature set (as announced) that we can expect to have at RTM.


Live Migration

This is probably the most compelling new feature and certainly the most anticipated in Windows Server 2008 R2 Hyper-V.  In a nutshell, live migration provides the ability to move running VMs from one physical host to another (currently, within a single cluster) without any service interruption or any downtime as perceived by end-users.  I’ll detail more about live migration vs. Quick Migration and the requirements for each in another post.


Dynamic VM storage

We can now hot-add / remove storage!  This feature allows the addition and removal of both Virtual Hard Drive (VHD) files and pass-through disks to the existing SCSI controllers of VMs – while a VM is running!  Much needed and much appreciated, Microsoft!  Thanks…

Note: Hot add and removal of storage requires the Hyper-V Integration Services supplied with Windows Server 2008 R2 to be installed in the guest operating system.  I think this is a small price to pay and something that you should really be doing anyway for the best functionality with your VMs.


Enhanced Processor Support

Have you ever wanted to run a 32-processor SQL Server 2008 Hyper-V VM but were frustrated with the limitation of 24 logical processors provided through Windows Server 2008 Hyper-V?  Well, this is going to make your day then…

2008 R2 Hyper-V will now support up to 32 logical processor cores.  It also introduces support for Second-Level Address Translation (SLAT) and CPU Core Parking. 

Funny Note: SLAT is not the same as the South Lake Union Trolley with its unfortunate acronym.  J  

Disclaimer: This may only be humorous to readers, local to the Seattle area.


Quote from Microsoft: “SLAT uses special CPU functionality available in Intel processors that support Extended Page tables and AMD processors that support Rapid Virtualization Indexing to carry out some VM memory management functions that reduce the overhead of translating guest physical address to real physical addresses.  This significantly reduces Hypervisor CPU time and saves memory for each VM, allowing the physical computer to do more work while utilizing fewer system resources.  CPU Core Parking enables power savings by scheduling VM execution on only some of a server’s CPU cores and placing the rest in a sleep state.”


Enhanced Networking Support

Finally, a couple of networking capabilities from earlier Windows releases are making their way into the Virtualization stack (along with one feature new for just the virtual world)…

The first feature extension is Jumbo Frames support in your VMs.  This feature enables virtual machines to use Jumbo Frames up to 9014 bytes in size if the underlying physical network supports it.  Supporting Jumbo frames reduces the network stack overhead incurred per byte and increases throughput.  In addition, there is also a significant reduction of CPU utilization due to the fewer number of calls from the network stack to the network driver. 

TCP Chimney, which allows the offloading of TCP/IP processing to the network hardware, has also been extended to work in the virtual world.  TCP Chimney improves VM performance by allowing the VM to offload network processing to hardware, especially with networks over 1 Gigabit.   This feature will prove of particular value when VMs are involved in large data transfers.

 As for the new feature, the Virtual Machine Queue (VMQ) feature allows the NICs of the physical computer to use DMA to place the contents of packets directly into VM memory, increasing I/O performance.


Cluster Shared Volumes (CSV)

Cluster Shared Volumes (CSV) is another of the big additions to Server 2008 R2.  While it is commonly misunderstood to be a requirement for Hyper-V live migration (it is not required; other third-party products can also provide the shared volume support needed to permit live migration to function), it is perhaps the best solution as it is in the box with R2 and it simply works (and it’s free).

CSV is a significant departure from the last 13+ years of cluster disk architecture from Microsoft, in that it now provides access to a single volume from multiple cluster nodes simultaneously. I’ll get into the details of CSV in another blog post, but suffice it for now to say that CSV greatly simplifies the process of working with SAN volumes in large clusters (no more drive letter vs. volume GUID deliberations) and enables us to use live migration without additional third-party software.



Exchange Server 2010 Beta Released to the Public

In case you’re interested in Exchange Server happenings, the Beta of Exchange Server 2010 has been released and you can download it now!



Download Microsoft Exchange Server 2010 Beta.


Offer lower-cost, high-value communications solutions to your customers.

Always an industry standard, Microsoft Exchange Server 2010 has been improved in three major ways.

It is more flexible and reliable. And easier to deploy and administer. So it can save you and your customers money by reducing IT overhead and help-desk loads. Online options let you and your customers leverage cost and technology advantages of cloud-based solutions, which also support data backup, storage, and disaster recovery.

It delivers anywhere access. Let’s face it. Nothing is going to work better with Microsoft Office Outlook-enabled devices than Exchange. But interoperability goes beyond that. Beyond Windows without walls. Beyond even the Windows Mobile software platform. Exchange Server 2010 can help users access all their communications from a single location, wherever it might be. Whatever the device. Whatever the platform or browser. So everyone gets more done.

It provides better communications protection and compliance. Exchange Server 2010 delivers integrated information-loss prevention and compliance tools that make it easier to protect communications and meet regulatory requirements. Built-in defenses against viruses and junk e-mail. Support for an array of third-party security products. The ability to respond quickly to litigation and discovery requests without workflow disruption. It’s a package your customers will want.

Test-drive the new Exchange Server—download the beta version now and share it with your customers.



Exchange Server 2010 Product Overview.


What’s new in Exchange Server 2010?


MSDN Exchange Server Developer Center and Exchange Server 2010 TechCenter.


Introducing Windows 7

Here’s a free 26 minute video presentation (Learning Snack) from Microsoft to help you get up to speed with Windows 7. 

 Free Learning Snack Offer: Introducing Windows 7
See the Windows 7 client operating system technologies and capabilities that reduce operating costs and improve performance, security, and reliability. This Learning Snack offer is a free, interactive presentation that can help you get up to speed quickly.

There’s a lot more of these “Learning Snacks” like this one on different topics, accessible from here: http://www.microsoft.com/learning/snacks/default.mspx – Topic include Virtualization, Windows Server 2008, Silverlight, etc.

Vista is an "Unsupported Guest OS?"

Have you ever seen the “Unsupported Guest OS” error message below when trying to stand up a Vista VM in Hyper-V?


The error text reads: “An error has occurred: The specified program requires a newer version of Windows.”  Huh?…newer than Vista? 

Well, it turns out that this is only experienced with Vista RTM…not with an integrated SP1 build of Vista.  While it’s becoming less and less likely that you’re working with just the RTM bits for Vista, it can come up for some folks and can be a huge time-sink to resolve.

In short, the fastest way around this problem is simply to use a slipstreamed SP1 build of Vista and you’ll avoid the whole issue.  However, if for some reason this isn’t feasible, here’s a brief description of a couple of solutions for this issue.

The main challenge is that there is no network card (NIC) installed in a basic Vista RTM Hyper-V VM (due to the lack of support for the Integration Services/Components).   Two approachs to resolving this:

1. Use the Vista SP1 CD / .ISO file and mount it as a CD/DVD for the VM. 
2. Shut down the Vista RTM VM, Add a Legacy Network Adapter, reboot, download Vista SP1.

After either option,

  • Install SP1
  • Reboot
  • Install the Hyper-V Integration Services
  • Reboot again

You should be fine at this point.  If you’ve chosen to install the Legacy Network Adapter, you can safely remove this extraneous hardware at the final reboot if you wish.


The technical reason for this is that Windows Server 2008 and Vista Service Pack 1 (based on the same code base) are the first 2 OSes considered to be “fully enlightened.”  This includes both driver enlightenment and kernel enlightenment.  What each of these terms refer to is the way in which the Hyper-V hypervisor interacts with the underlying hardware for a given OS.  Vista RTM didn’t have the same level of enlightenment support, hence the lack of synthetic device support.  There’s a great reference to Hyper-V terminology over on Ben’s blog: http://blogs.msdn.com/virtual_pc_guy/archive/2008/02/25/hyper-v-terminology.aspx 


Hyper-V Licensing Explained!

I’ve spoken to a lot of people who have expressed a lot of confusion about the OS licensing model when virtualizing systems using Hyper-V products.

There are some simple guidelines to observe when planning your Hyper-V infrastructure to take advantage of the licensing models for each edition of Windows Server 2008.

First, a term definition: Microsoft uses the term “OSE” to refer to an operating system environment, either physical or virtual.  Also, Microsoft refers to a “processor” in the context of a single processor socket on the motherboard.  This calculation is not affected when considering multiple core processors or hyper-threading capabilities on certain processor types.


Microsoft Hyper-V Server 2008, the latest product is a free download from Microsoft.  While this initially seems like the only answer to your needs, remember that Hyper-V Server provides no licensing for OSEs.  Each virtual OSE requires its own licensing.  It is also limited in terms of support for total RAM, number of processors and has no Quick Migration or High Availability capabilities.


Windows Server 2008 Standard Edition provides a single license to run a single instance of the software.  My understanding of these terms is that this permits you to run a single virtual OSE on top of the Standard Edition server without requiring additional licenses.  This arrangement also means that you are only permitted to use the physical server itself to run the Hyper-V virtualization software and to manage the OSEs on the server. 

Standard Edition is the most cost-effective if you want to run up to three simultaneous instances in a virtual OSE on the server.


Windows Server 2008 Enterprise Edition expands upon these terms, providing licensing for up to four simultaneous virtual OSEs in addition to the physical OSE.  You can run either Standard or Enterprise Edition in the virtual OSEs. 

Enterprise Edition is most cost-effective if you want to run four simultaneous instances in a virtual OSE per processor. Enterprise Edition is licensed by server, not per processor, but more than one Enterprise Edition license may be assigned to a server to have the rights to run more than four instances of Windows Server. For example, one license for Enterprise Edition for a one-processor server running four instances of Windows Server in a virtual OSE is slightly less expensive than one Datacenter processor license. And, two licenses for Enterprise Edition for a two-processor server running eight instances of Windows Server in a virtual OSE is slightly less expensive than two processor licenses for Datacenter Edition.


Windows Server 2008 Datacenter Edition completes the journey, with unlimited licensing for virtual OSEs.  You can run Standard, Enterprise or Datacenter in the virtual OSEs.

While Datacenter Edition is licensed by processor, not per server, it is most cost-effective for running more than four instances per processor. At four instances per processor, Datacenter Edition is slightly more expensive than Enterprise Edition, but provides room to add instances in a virtual OSE on the server at no additional cost. The flexibility gained from “unlimited” virtualization rights reduces concern of licensing compliance.


Microsoft Hyper-V Server 2008

Windows Server 2008 Standard

Windows Server 2008 Enterprise

Windows Server 2008 Datacenter

No Licenses

1 Physical + 1 Virtual

1 Physical + 4 Virtual

1 Physical + unlimited virtual


There are two great Windows Server Virtualization Calculators available online to help you estimate your needs and the cost impact of each edition. You can find them here:  



One last note is that Datacenter is no longer an OEM-only SKU.  The availability of Datacenter changed back in the Server 2003 R2 days and has continued through the Server 2008 release.


Happy Virtualizing!