With the latest beta version of Windows Server 2008 (Longhorn) shipping last month, we get another step closer to release to manufacturing (RTM) and to the beta release of Microsoft's new hypervisor-based virtualization, code-name Viridian, now officially named Windows Server Virtualization (WSV). Microsoft has promised that as Windows Server 2008 rolls out this fall, and ultimately goes RTM by year end, that they will roll out the beta version of WSV. The RTM for WSV is still slated for release within 180 days of Windows Server 2008 RTM as a Service Pack, according to Microsoft, but without several originally planned key features (see part two of this column).
As the channel prepares for the Windows Server 2008 OS release and for WSV within 6 months after that, it is helpful to understand where WSV fits. Specifically, this column discusses WSV vs. the current Virtual Server product (which was just updated with SP1).
Microsoft hypervisor vs. hosted virtualization
WSV will be Microsoft's first virtualization offering, utilizing a hypervisor approach (already used by VMware ESX and Xen), as opposed to the hosted approach used by Microsoft Virtual Server (and VMware Server).
Hosted virtualization means there is a base operating system running at the lowest layer above the hardware, with the virtualization capability layered on top. Since all I/O operations must past through three levels of software (the native OS, the virtualization layer, and the guest OS), hosted solutions incur more overhead and are not very efficient, particularly an issue for larger environments. (In the SMB space, where simplicity often wins out over performance, both Virtual Server and VMware have gained some traction, while enterprises are looking for hypervisor solutions).
Hypervisors run as a thin layer directly on top of the hardware, yielding much greater efficiency. The guest operating systems (virtual machines) then run directly on top of the hypervisor.
WSV (Viridian) vs. Virtual Server
The WSV hypervisor will be Microsoft's enterprise solution, running only on 64-bit processors with either Intel-VT or AMD-V (hardware assists for virtualization). In addition to the added efficiency of the hypervisor architecture, it will offer additional capabilities over Virtual Server such as support for 64-bit guest operating systems (virtual machines), and multi-processor support at the guest level. It will include migration capability for moving virtual machines from one system to another for planned or unplanned outages, including patching and hardware maintenance (but will not include live migration as originally intended). High Availability for WSV will come by way of Windows Server Failover Clustering, which is newly improved in Windows Server 2008 (see my last SearchServerVirtualization column on virtualization availability
WSV will be implemented as one of the eight roles of Windows Server 2008, by installing the new Server Core, and then adding the virtualization components. The new Server Core architecture aims to eliminate the unneeded parts of the OS when running in various roles such as virtualization, both to reduce complexity and increase security by having a smaller "surface area."
Virtual Server, which was just updated to SP1, will continue as the solution for x86 boxes not upgrading to 64-bit. SP1 adds the ability to leverage Intel-VT and AMD-V for performance improvements when running Red Hat Enterprise Linux (RHEL), SUSE Linux or Solaris (note that running Windows under Virtual Server will have no performance improvement). SP1 also adds support for Volume Shadow Copy Services (VSS), offering capabilities for various backup software from vendors such as CommVault and CA to utilize virtual snapshots.
Windows Licensing for WSV will work the same as it does currently for Virtual Server or other virtual environments. Enterprise Edition allows up to four instances of Windows to run on one physical system. Datacenter Edition allows an unlimited number of Windows virtual machines to run on the same hardware.
Part two of this column will look closer at what will and will not be there in the WSV initial release, as well as Microsoft virtualization management with Systems Center Virtual Machine Manager (VMM), and getting up to speed on WSV.
For more information read part two, Windows Server 2008 virtualization: Delays and new features.
Barb Goldworm is president and chief analyst of Focus Consulting a research, analyst and consulting firm focused on systems, software, and storage. Barb has spent thirty years in various technical, marketing, senior management, and industry analyst positions with IBM, Novell, StorageTek, Enterprise Management Associates, and multiple successful startups. A frequent speaker, columnist, and author of numerous white papers and research studies, she has just released a book entitled Blade Servers and Virtualization: Transforming Enterprise Computing While Cutting Costs. She recently chaired the Server Blade Summit conference on blades and virtualization, has been the keynote speaker at multiple Virtualization Summits, created and chaired the network storage component of Interop, and has been one of the top three ranked analyst/knowledge expert speakers at Storage Networking World. firstname.lastname@example.org>Email Barb directly.