Hyper-V is also available as a freely downloadable version through the Microsoft Hyper-V Server 2008. This version is a self-contained, single-purpose version of Windows Server 2008 that has been customized to support the Hyper-V role.
It is based on the Standard edition of Windows Server 2008 and therefore lacks support for high availability and is limited to 32 gigabytes (GB) of RAM. Each machine you deploy with Hyper-V Server will be a stand- alone host server and will not be able to provide service redundancy for the virtual machines you deploy on them.
Hyper-V Server also relies on the Server Core interface and does not provide a graphical environment. Everything is run through a command line. Yet because Hyper-V Server is based on the core Windows Server code, it provides support for remote administration much the same way that Windows Server 2008 Hyper-V does when run in a Server Core installation.
Because of the Hyper-V Server’s feature set, Microsoft recommends that you use it in test and development environments, for basic server consolidation where host server high availability is not a requirement, or in branch office consolidation scenarios.
Keep this in mind as you choose which edition of Hyper-V to deploy in your environments. Note that as a free product, Hyper-V Server does not include any virtualization rights for Windows Server operating systems. To obtain additional virtualization rights, you must purchase a version of Windows Server 2008 that includes Hyper-V.
To simplify the installation and deployment of Hyper-V Server, Microsoft has included a custom configuration menu—something that is not available in Server Core installations of Windows Server 2008.
Because it is integrated into the Windows Server operating system, Hyper-V benefits from the existing Windows Server feature set. In addition, Hyper-V relies on the Designed for Windows hardware specification, which gives it access to thousands of validated platform configurations. Here the specific features of Hyper-V:
Access Control through Authorization Manager (AzMan) - Hyper-V includes support for role-based access control (RBAC) through the use of Authorization Manager. This allows organizations to create custom security roles to delegate specific activities within Hyper-V.
Extensibility - Hyper-V is integrated into the Windows Management Instrumentation (WMI) and includes several application programming interfaces (APIs) in support of third-party tool and utility development.
Fault Tolerance - Hyper-V can rely on the Failover Clustering feature of Windows Server 2008 to ensure that host servers are highly available. You must use either the Enterprise or the Datacenter editions of Windows Server 2008 to gain access to this feature. Virtual machines running in Hyper-V can take advantage of both the Failover Clustering feature and Network Load Balancing at the virtualization layer for fault tolerance.
Guest OS Support - Hyper-V supports the operation of both 32-bit and 64-bit virtual machines running a wide variety of operating systems.
Hardware Sharing Architecture - Hyper-V relies on a hardware sharing architecture that provides access and monitors utilization of core resources—disk, networking, video—through a virtual service provider (VSP)/ virtual service client (VSC) architecture.
Improved Windows Server 2008 VM Performance - Because Windows Server 2008 includes the Hyper-V role, all virtual machines built on Windows Server 2008 automatically include integration components to improve VM performance.
Integration to Windows Server 2008 - Hyper-V can rely on a multitude of certified devices and physical machine configurations because it is built on the x64 version of the Windows Server code.
Linux Integration Components - Hyper-V includes SUSE Linux Enterprise Server 10 SP1 x86 and x64 integration components. This provides improved performance for guest Xen-enabled Linux operating systems when running as virtual machines on Hyper-V.
Quick Migration - When running in a failover cluster, Hyper-V hosts can move a running virtual machine from one host to another with minimal service interruption. The virtual machine is paused on one host server and restored on another.
Remote Administration - Hyper-V includes a stand-alone Hyper-V Microsoft Management Console (MMC) that can be installed separately to provide remote administration of all Hyper-V hosts running either Server Core, the full installation, or running on Hyper-V Server.
Server Core Integration - Hyper-V is available as a role in a Server Core installation, reducing the attack surface and the downtime associated with operating system updates on host servers.
Server Manager Support - Hyper-V is a role that is integrated into the Server Manager interface of Windows Server 2008. This facilitates the use of Hyper-V on full installations of Windows Server 2008. Note that Server Manager cannot manage remote instances of servers and therefore cannot be used to manage a Server Core installation of Hyper-V.
Settings Quick Reset - Administrators can quickly reset all check boxes and remove saved credentials from within the Hyper-V administration console.
Symmetric Multiprocessing Support - Virtual machines running in Hyper-V can rely on up to four virtual processors. However, the number of supported processors varies with the operating system installed in the guest VM.
Virtual Hard Disk (VHD) Tools - Hyper-V includes a set of tools that support the compaction, expansion, and inspection of virtual hard disk drives created with Hyper-V.
Virtual Machine Snapshots - Hyper-V supports the creation of point-in-time snapshots for virtual machines—images of a given state for the VM at a given time—and can create up to 50 snapshots per VM. Note that these VM snapshots are not to be confused with the snapshots taken by the Volume Shadow Copy (VSS) Service during backup operations.
Virtual Networking - Hyper-V includes a new virtual network switch that provides access to multiple network interface card types for each VM. The virtual network switch provides full support for features such as Network Load Balancing.
Virtual SCSI Support - Hyper-V supports up to four virtual SCSI controllers per virtual machine, giving your VMs access to a multitude of disks.
VM Manageability - Hyper-V provides support for importing and exporting virtual machine settings, letting you move VMs from host to host with little or no impact.
VM Memory Support - VMs running on Hyper-V can each access up to 64 GB of RAM.
Volume Shadow Copy Services (VSS) Support - Hyper-V includes support for VSS to allow the backup of running virtual machines through the use of VSS snapshots. This reduces the downtime that can be associated with VM backups.