Hi All,

Windows Server 2008 Hyper-V, hypervisor-based server virtualization technology, allows you to make the best use of your server hardware investments by consolidating multiple server worklaods as separate virtual machines (VMs) running on a single physical machine. With Hyper-V, you can also efficiently run multiple different operating systems concurrently, on a single server, and fully leverage the power of x64 computing.

When you’re planning a virtualization infrastructure with Hyper-V, please be sure to stay within the supported limits below. In addition, the limits discussed in this document are highly dependent on the underlying hardware server configuration.


Operating System Requirements

Windows Server 2008 includes Hyper-V as an available role. Hyper-V is included with:

· Windows Server 2008 Standard Edition (x64)

· Windows Server 2008 Enterprise Edition (x64)

· Windows Server 2008 Datacenter Edition (x64)

Note: That Hyper-V is an x64 Edition only technology and is not available for 32-bit (x86) or Itanium (IA64) editions.


Hardware Requirements

· Hyper-V requires an x64 processor with Hardware-assisted virtualization. This is available in processors that include a virtualization option; specifically, Intel VT or AMD Virtualization.

· Hardware Data Execution Protection (DEP) is also required and must be enabled. Specifically, you must enable Intel XD bit (execute disable bit) or AMD NX bit (no execute bit).


Virtual Machine Architecture Support

· Hyper-V offers support for:

o 32-bit (x86) operating systems

o 64-bit (x64) operating systems

Both 32-bit and 64-bit virtual machines can run concurrently.



· Windows Server 2008 Enterprise/Datacenter Editions

o System/Host Physical memory support: Up to 1 TB of physical memory

o Virtual Machine memory support: Up to 64 GB of memory per virtual machine

· Windows Server 2008 Standard Edition

o System/Host Physical memory: Up to 32 GB of physical memory

o Virtual machine memory support: Approximately ~31.5 GB total used for all running virtual machines



· Physical Processor support: Hyper-V is supported on systems with up to 16 logical processors; A logical processor can be a core or a hyper-thread. Examples include:

o Single processor/Dual core system = 2 logical processors

o Single processor/Quad core system = 4 logical processors

o Dual processor/Dual core system= 4 logical processors

o Dual processor/Quad core system=8 logical processors

o Quad processor/Dual core system= 8 logical processors

o Quad processor/Dual core, hyper-threaded systems=16 logical processors

o Quad processor/Quad core systems=16 logical processors

· Virtual Processor support: Up to 4 virtual processors per virtual machine

Note: Hyper-V may run on systems with greater than 16 logical processors; however these configurations are not supported.



· Up to 12 virtual network adapters per virtual machine

o 8 synthetic network adapters

o 4 emulated network adapters

· Each virtual network adapter can use either a static or dynamic MAC address

· Each virtual network adapter offers integrated VLAN support and can be assigned a unique VLAN channel

· Unlimited number of virtual switches with an unlimited number of virtual machines per switch


Physical Storage:

· Hyper-V offers flexible storage support such as:

o Direct Attach Storage (DAS): SATA, eSATA, PATA, SAS, SCSI, USB, FIrewire

o Storage Area Networks (SANs): iSCSI, Fiber Channel, SAS

o Network Attached Storage (NAS)


Virtual Hard Disks:

· Dynamically Expanding Virtual Hard Disks:

o Default type maximum size up to 2040 GB each

· Fixed Size Virtual Hard Disks:

o Maximum size up to 2040 GB each

· Pass-through disks

o No size limitation other than what is supported by the guest operating system

Virtual Storage Controllers:

· Virtual IDE

o Each virtual machine supports up to 4 IDE devices

o One IDE device must be a virtual disk (VHD or pass-through) for boot

· Virtual SCSI

o Each virtual machine supports up to 4 virtual SCSI controllers

o Each controller supports up to 64 disks for a total of 256 virtual SCSI disks PER virtual machine.


Virtual Storage:

· Total storage per virtual machine:

o Using virtual hard disks, each virtual machine supports 512 TB of storage per vm

o Using pass-through disks, this number is even greater depending on what is supported by the guest operating system;

· Virtual Machine Snapshots:

o Hyper-V supports up to 50 snapshots per virtual machine

· Virtual Machine Boot

o Virtual machines must boot from a virtual IDE device; however, that device can be backed by a wide array of storage options including:

1. Direct Attach Storage (DAS): SATA, eSATA, PATA, SAS, SCSI, USB, FIrewire

2. Storage Area Networks (SANs): iSCSI, Fiber Channel, SAS

3. Network Attached Storage (NAS)

IMPORTANT: Although the I/O performance of physical SCSI and IDE can differ significantly, this is not true for the virtualized SCSI and IDE devices in Hyper-V. Hyper-V IDE and SCSI storage devices both offer equally fast high I/O performance when integration services are installed in the guest operating system.


Virtual CD/DVD:

· Maximum number of virtual CD/DVDs: By default, each virtual machine is provided one virtual CD/DVD. However, each virtual machine can support up to 3 virtual DVD drives per virtual machine (on the virtual IDE bus only) as one IDE device must be used as a virtual boot device.

· Pass-through CD-DVD:

o For security purposes, only one virtual machine can access a physical CD/DVD at a time.

· Virtual CD/DVD:

o Hyper-V supports reading virtual CD/DVD .ISO files


Virtual Serial (COM) Ports

· Each virtual machine supports up to 2 virtualized COM ports that can be used to communicate with a physical server (local or remote) via a serial named pipe.


Virtual Floppy Drive

· Each virtual machine supports up to 1 virtual floppy drive


Number of Virtual Machines:

· Supports up to 128 concurrent running virtual machines

· Supports up to 512 configured virtual machines