Advantages of Hyper-V by liwenting


									Hyper V - Windows Server Virtualization

   Page 1 of 11   Clarion Technologies Pvt. Ltd, Pune   Version 1.0
Table of Contents
 What is server virtualization and Microsoft Hyper-V? ........................................................................................................3

 Virtualization as an IT Organization Strategy ......................................................................................................................3
      Virtualization Driven by Hardware Capabilities ....................................................................................... 3
      Virtualization Driven by the Desire to Go “Green” .................................................................................. 3
      Virtualization Driven by Lower Costs ....................................................................................................... 4

 VMWare vs Hyper V                                              4

 Architecture :                                                 6

 Advantages of Hyper-V                                          9

 Minimum system requirements                                    11

 Books & References :                                           11

                Page 2 of 11                       Clarion Technologies Pvt. Ltd, Pune                                      Version 1.0
     What is server virtualization and Microsoft Hyper-V?

Server virtualization is the ability for a single system to host multiple guest operating system
sessions and effectively taking advantage of the processing capabilities of very powerful servers.

Most servers in data centers run under 5% to 10% processor utilization, meaning that excess
capacity on the servers goes unused.

By combining the workloads of multiple servers onto a single system, an organization can better
utilize the processing power available in its networking environment.

     Virtualization as an IT Organization Strategy
Just 2 to 3 years ago, virtualization was used primarily as a test environment solution for
information technology (IT) departments. If an IT administrator wanted to test new software,
rather than building up a full physical server and loading software on that system,the
administrator would install the software on a virtual server system and fiddle with the software off
the virtual server. A virtual server enabled the IT administrator to load up several different test
systems without purchasing or setting up separate computer systems.

However, virtual servers were not considered reliable or robust enough to handle the day to-
day demands of an organization’s IT needs. Much of that belief stemmed from the limitations
of computer hardware capacity that existed just half a decade ago; server systems were
underutilized but still taking up 20% to 30% of system capacity.

       Virtualization Driven by Hardware Capabilities
Only recently, with the release of dual-core or quad-core processors and 64-bit operating
systems, have servers gone from having 2 or 4 core processors to easily 8 to 16 core
processors, and from 4GB of RAM to 16, 32, or 64GB of RAM. Now instead of running at
20% to 30% capacity, servers are running at 2% to 3% capacity.

       Virtualization Driven by the Desire to Go “Green”
Whereas hardware provided significant excess capacity to consolidate server processes into
fewer server systems, the social interest to go “green” has driven organizations to decrease
their power consumption and improve their resource utilization.

Virtualization enables an organization to decrease the number of physical computers they need to
purchase, and in doing so also decreases the power and air-conditioning cooling demands that
computer systems require. An organization that can decrease the physical number of its servers
by 50% to 75% can decrease their electrical power requirements by a similar percentage.

Virtualization also decreases the computer data center “sprawl,” whereas the increase of
physical servers in the recent past caused organizations to continue to increase the square
footage of their data centers. With virtualization physical server systems, an organization can
decrease the size of their data centers and decrease the overall footprint required to host their
information systems.

       Virtualization Driven by Lower Costs
Many organizations now realize that fewer server systems and lower demands on electrical
power, air-conditioning costs, and the decrease in data center space are lowering the cost
of IT operations. To increase profitability, or just to manage overhead costs, virtualization
enables organizations to decrease costs and better utilize IT resources.

     VMWare vs Hyper V
There are other similar products like Hyper -V available in the market amongst most of the
products available VMWare is one of the most popular.

Figure Below shows the comparison between VMWare and Hyper V features.

                                             [Fig 1]
     Architecture :
Hyper-V is a hyper visor-based virtualization technology for x64 versions of Windows Server 2008.
The hyper visor is the processor-specific virtualization platform that allows multiple isolated
operating systems to share a single hardware platform.

Hyper-V supports isolation in terms of a partition. A partition is a logical unit of isolation,
supported by the hyper visor, in which operating systems execute. The Microsoft hyper visor must
have at least one parent, or root, partition, running Windows Server 2008 64-bit Edition. The
virtualization stack runs in the parent partition and has direct access to the hardware devices. The
root partition then creates the child partitions which host the guest operating systems. A root
partition creates child partitions using the hyper call application programming interface (API).

Partitions do not have access to the physical processor, nor do they handle the processor
interrupts. Instead, they have a virtual view of the processor and run in a virtual memory address
region that is private to each guest partition. The hyper visor handles the interrupts to the
processor, and redirects them to the respective partition. Hyper-V can also hardware accelerate
the address translation between various guest virtual address spaces by using an Input Output
Memory Management Unit (IOMMU) which operates independent of the memory management
hardware used by the CPU. An IOMMU is used to remap physical memory addresses to the
addresses that are used by the child partitions.

Child partitions also do not have direct access to other hardware resources and are presented a
virtual view of the resources, as virtual devices (VDevs). Requests to the virtual devices are
redirected either via the VMBus or the hypervisor to the devices in the parent partition, which
handles the requests. The VMBus is a logical inter-partition communication channel. The parent
partition hosts Virtualization Service Providers (VSPs) which communicate over the VMBus to
handle device access requests from child partitions. Child partitions host Virtualization Service
Consumers (VSCs) which redirect device requests to VSPs in the parent partition via the VMBus.
This entire process is transparent to the guest operating system.

Virtual Devices can also take advantage of a Windows Server Virtualization feature, named
Enlightened I/O, for storage, networking, graphics, and input subsystems. Enlightened I/O is a
specialized virtualization-aware implementation of high level communication protocols (such as
SCSI) that utilize the VMBus directly, bypassing any device emulation layer. This makes the
communication more efficient but requires an enlightened guest that is hypervisor and VMBus
aware. Hyper-V enlightened I/O and a hypervisor aware kernel is provided via installation of
Hyper-V integration services. Integration components, which include virtual server client (VSC)
drivers, are also available for other client operating systems. Hyper-V requires a processor that
includes hardware assisted virtualization, such as is provided with Intel VT or AMD Virtualization
(AMD-V) technology.
The following diagram[Fig 2] provides a high-level overview of the architecture of a Hyper-V
environment running on Windows Server 2008.
                                              [Fig 2]

Acronyms and terms used in the diagram above are described below:
      APIC – Advanced Programmable Interrupt Controller – A device which allows priority levels
       to be assigned to its interrupt outputs.
      Child Partition – Partition that hosts a guest operating system - All access to physical
       memory and devices by a child partition is provided via the Virtual Machine Bus (VMBus) or
       the hypervisor.
      Hypercall – Interface for communication with the hypervisor - The hypercall interface
       accommodates access to the optimizations provided by the hypervisor.
      Hypervisor – A layer of software that sits between the hardware and one or more
       operating systems. Its primary job is to provide isolated execution environments called
       partitions. The hypervisor controls and arbitrates access to the underlying hardware.
      IC – Integration component – Component that allows child partitions to communication
       with other partitions and the hypervisor.
      I/O stack – Input/output stack
      MSR – Memory Service Routine
      Root Partition – Manages machine-level functions such as device drivers, power
       management, and device hot addition/removal. The root (or parent) partition is the only
       partition that has direct access to physical memory and devices.
      VID – Virtualization Infrastructure Driver – Provides partition management services, virtual
       processor management services, and memory management services for partitions.
      VMBus – Channel-based communication mechanism used for inter-partition
       communication and device enumeration on systems with multiple active virtualized
       partitions. The VMBus is installed with Hyper-V Integration Services.
   VMMS – Virtual Machine Management Service – Responsible for managing the state of all
    virtual machines in child partitions.
   VMWP – Virtual Machine Worker Process – A user mode component of the virtualization
    stack. The worker process provides virtual machine management services from the
    Windows Server 2008 instance in the parent partition to the guest operating systems in the
    child partitions. The Virtual Machine Management Service spawns a separate worker
    process for each running virtual machine.
   VSC – Virtualization Service Client – A synthetic device instance that resides in a child
    partition. VSCs utilize hardware resources that are provided by Virtualization Service
    Providers (VSPs) in the parent partition. They communicate with the corresponding VSPs in
    the parent partition over the VMBus to satisfy a child partitions device I/O requests.
   VSP – Virtualization Service Provider – Resides in the root partition and provide synthetic
    device support to child partitions over the Virtual Machine Bus (VMBus).
   WinHv – Windows Hypervisor Interface Library - WinHv is essentially a bridge between a
    partitioned operating system’s drivers and the hypervisor which allows drivers to call the
    hypervisor using standard Windows calling conventions
   WMI – The Virtual Machine Management Service exposes a set of Windows Management
    Instrumentation (WMI)-based APIs for managing and controlling virtual machines.
     Advantages of Hyper-V
The advantages of running enterprise-level solutions in a Hyper-V virtualized environment include
the following:
    1. Consolidation of hardware resources - Multiple physical servers can be easily
       consolidated into comparatively fewer servers by implementing virtualization with Hyper-V.
       Consolidation accommodates full use of deployed hardware resources.
    2. Ease of administration:
            Consolidation and centralization of resources simplifies administration.
            Implementation of scale-up and scale out is accommodated with much greater ease.
    3. Significant cost savings:
            Hardware costs are significantly reduced because multiple virtual machines can run
              on a single physical machine, therefore, a separate physical machine is not required
              for every computer.
            Hyper-V licensing costs are included with the license cost of Windows Server 2008.
              Hyper-V can also be purchased for use as a stand-alone product that can be
              installed on Windows Server 2008 Server Core.
    4. Fault tolerance support through Hyper-V clustering – Because Hyper-V is a cluster
       aware application, Windows Server 2008 provides native host clustering support for virtual
       machines created in a Hyper-V virtualized environment.
    5. Ease of deployment and management:
            Consolidation of existing servers into fewer physical servers simplifies deployment.
            A comprehensive Hyper-V management solution is available with System Center
              Virtual Machine Manager. For more information about System Center Virtual Machine
              Manager, see
    6. Key Hyper-V performance characteristics:
            Improved hardware sharing architecture - Hyper-V provides improved access
              and utilization of core resources, such as disk, networking, and video when running
              guest operating systems with a hypervisor-aware kernel and which are equipped
              with requisite virtual server client (VSC) code (known as Hyper-V enlightened I/O).
              Enlightenments are enhancements made to the operating system to help reduce the
              cost of certain operating system functions like memory management. Presently,
              both Windows Server 2008 and Windows Vista support Hyper-V enlightened I/O and
              a hypervisor aware kernel via installation of Hyper-V integration services.
              Integration components, which include VSC drivers, are also available for other
              client operating systems.
              Disk performance is critical for disk I/O intensive enterprise applications such as
              Microsoft BizTalk Server and in addition to Hyper-V enlightened I/O; Hyper-V
              provides “Pass-through” disk support which provides disk performance on par with
              physical disk performance. Note that “Pass-through” disk support provides improved
              performance at a small cost to convenience. “Pass-through” disks are essentially
              physical disks/LUNs that are attached to a virtual machine and do not support some
              of the functionality of virtual disks, such as Virtual Machine Snapshots.
            Processor hardware-assisted virtualization support – Hyper-V takes full
              advantage of processor hardware assisted virtualization support that is available
              with recent processor technology.
            Multi-core (SMP) guest operating system support – Hyper-V provides the
              ability to support up to four processors in a virtual machine environment, which
          allows applications to take full advantage of multi-threading functionality in a virtual
          machine. Virtual machines running Windows Server 2003 support up to two
          processors, therefore, BizTalk Server 2006 can support only two-cores.
        Both 32-bit and 64-bit guest operating system support – Hyper-V provides
          broad support for simultaneously running different types of operating systems,
          including 32-bit and 64-bit systems across different server platforms, such as
          Windows, Linux®, and others.
7. Proven track record - Key Microsoft Web sites MSDN
   ( and TechNet
   ( are hosted in Hyper-V
8. Comprehensive product support – Because Microsoft enterprise applications (such as
   Exchange Server and SQL Server) are fully tested running in Hyper-V, Microsoft provides
   code fix support for these applications when deployed and run in a Hyper-V environment.
9. Scalability – Additional processing power, network bandwidth, and storage capacity can be
   accomplished quickly and easily by apportioning additional available resources from the
   host computer to the guest virtual machine(s). This may require that the host computer is
   upgraded or that the guest virtual machines are moved to a more capable host computer.
    Minimum system requirements

Component                  Minimum requirements   Recommended
Processor                  1GZ                    AMD 64 or Intel EM64T (x64)
                                                  processor with at least 2
                                                  core or even 4 or 8 core 2GHz
                                                  or faster
Memory                     512MB of RAM           8GB of RAM, or even 16GB to
                                                  32GB, depending on the
                                                  number of virtual guests
Disk space                 8GB                    8GB for the base installation of
                                                  Windows 2008, plus
                                                  enough disk space for all the
                                                  virtual guest session disks

    Books & References :

  2) Windows server 2008 unleased.

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