Virtualization is one of today’s hottest IT technologies, and
Windows Server 2008’s new native virtualization feature,
Hyper-V, is a significant new competitor that has the potential
to change the market. VMware ESX Server is the current market
favorite. To make an informed decision about Hyper-V, you
need to understand how the architectures of the two products
compare. In addition, Hyper-V introduces some important new
features, and you’ll want to
see how Hyper-V and the
older Virtual Server 2005 R2
relate to each other. Finally, to
enrich your understanding of
Hyper-V I’ll show you how to set
it up and use it.
Prerequisites for
Hyper-V
Unlike Microsoft’s Virtual Server
2005 R2, which runs on both
32-bit and 64-bit systems, Hyper-V
requires an x64-based system that
has either Intel-VT or AMD-V support.
In addition, the host system’s
CPU must have data execution
protection enabled (the Intel XD
bit or the AMD NX bit). Microsoft
will provide Hyper-V virtualization
technology with the following versions of the Windows Server 2008.
- Server 2008, Standard: $999 with five Client Access Licenses (CALs)
- Server 2008, Enterprise: $3,999 with 25 CALs
- Server 2008, Datacenter: $2,999 per processor
Like the Windows Server 2003 R2, Enterprise and Datacenter Editions,
the Server 2008, Enterprise Edition allows up to four virtual Windows instances with no additional licensing
costs, and Server 2008 Datacenter Edition
allows an unlimited number of virtual Windows
instances with no additional licensing
costs. You can use Hyper-V with both the full
Server 2008 installation, or with Server Core
for any of the Server 2008 editions. In addition
Microsoft will offer a standalone version called
Hyper-V Server for $29.
Windows Server Hyper-V
Architecture
Designed to compete with VMware’s ESX
Server, Hyper-V has been built from scratch
based on a new microkernel architecture. Figure
1, shows an overview of the new
Server 2008 Hyper-V architecture. For a quick
comparison of ESX Server and Hyper-V, see
the sidebar “Feature for Feature: VMware ESX
Server vs. Microsoft Hyper-V.”
Unlike Virtual Server’s hosted virtualization
model, which requires installing the virtualization
software on top of a host OS, Hyper-V is
a virtualization layer that runs directly on the
system hardware with no intervening host OS.
The Hyper-V architecture consists of the bare
metal microkernel hypervisor and parent and
child partitions.
All Hyper-V implementations have one
parent partition. This partition manages the
Hyper-V installation. The Windows Server
Virtualization console runs from the parent
partition. In addition, the parent partition is
used to run thread-supported legacy hardware
emulation virtual machines (VMs). These
older emulation-based VMs are essentially
the same as the VMs that run under a hosted
virtualization product such as Virtual Server.
Guest VMs run on Hyper-V child partitions.
Hyper-V’s child partitions support two types of
VM: high performance VMBus-based VMs or
hosted emulation VMs. VMBus VMs include
Windows Server 2003, Windows Vista, Server
2008, and Xen-enabled Linux. The new VMBus
architecture is essentially a high performance
in-memory pipeline that connects Virtualization
Service Clients (VSCs) in the guests
with the host’s Virtual Service Provider (VSP).
Hosted emulation VMs support guest OSs that
don’t support the new VMBus architecture.
These OSs include, Windows NT, Windows
2000, and non-Xen enabled Linux, like SUSE
Linux Server Enterprise 10.
Hyper-V and Virtual Server
Server 2008
Hyper-V introduces capabilities
that aren’t available with Virtual Server 2005
R2. Running exclusively on the x64 platform,
Hyper-V supports host systems with up to 1TB
of RAM, and Hyper-V doesn’t limit the number
of active VMs; the only limitation comes from
the capabilities of the host server hardware. In
addition, the Hyper-V VMs are more scalable
than Virtual Server VMs. Hyper-V supports
both 32-bit and 64-bit guest OSs. Not only can
guest VMs take advantage of Hyper-V’s higher
performing VMBus architecture, but guest
VMs also can use more RAM and CPU than
Virtual Server offers. Virtual Server 2005 R2
has no support for virtual SMP and is limited
to 3.6GB of RAM per VM. Hyper-V supports up
to 4 virtual processors per VM and up to 32GB
of RAM per VM. To take full advantage of this
support, the host system must have at least 4
cores and more than 32GB of physical RAM.
Hyper-V provides new storage features.
Storage Area Network (SAN) support lets
you boot VMs and implement guest-to-guest
failover clustering, as well as virtual server host
failover clustering. Hyper-V also introduces the
pass-through VM access storage feature. With Hyper-V, you can access virtual
hard disk (VHD) images without
mounting the VHD image in a
running VM. Hyper-V can also take
advantage of Volume Shadow Copy
Service (VSS) for live VM backup.
On the networking side, Hyper-V
includes a new virtual switch with
support for Windows Network
Load Balancing (NLB) across VMs
on separate servers. In addition,
Hyper-V allows multiple snapshots
of running VMs with the ability
to revert back to any of the saved
snapshots.
Installing Hyper-V
Hyper-V is not installed in Server
2008 by default. To install Hyper-V,
you use the Server 2008 Server Manager. Click
Start, Programs, Administrative Tools, and
then select the Server Manager option. In
Server Manager, add the virtualization role
by clicking Add Roles, which displays the Add
Roles Wizard shown in Figure 2.
In the Add Roles Wizard, check the Windows
Server virtualization role. Then click Next and
step through the wizard’s screens to learn about
and configure Hyper-V. The wizard first explains
that you might need to configure your BIOS for
virtualization support, and it provides links to
Windows Server Virtualization Online Help files.
Next, the wizard prompts you for the Local Area
Connections that you want to associate with
your virtual networks. By default, the wizard
creates one virtual network for each physical
network adapter that’s installed. Next, you’re
asked to confirm your selections and prompted
to restart your system.
AMD-V systems have virtualization support
enabled by default. In contrast, if your
system uses Intel-VT virtualization, check your
system’s BIOS configuration during the boot
process and make sure that virtualization is
enabled. For systems with Intel motherboards,
press F2 during the boot process to see the
BIOS configuration. You can set the Enable VT
option to enable virtualization support in the
processor.
After the system reboots, the Resume Configuration
Wizard screen appears. Use it to
finish installing the Windows Server Virtualization
role. The new Windows Server Virtualization
role will then be listed under Server
Manager’s installed roles node.