Tuesday, January 18, 2011

Some details about the Integration Components/Integration Services (Hyper-V Architecture part 2)

When an operating system is supported for Hyper-V, it means that it supports the Integration Components/Integration Services.

This is an optimization technique for a guest operating system to make it aware of virtual machine environments and to shape its behavior when it is running in a virtual environment. There are some important and great benefits with the IC. The VSC (Virtual Service Client) is a synthetic device that resides in a child partition. When you install the IC you also install the VSC that makes the VM able to communicate over the VMBus – with the VSP (Virtual Service Provider).
The VSP provides the needed support for those synthetic devices in the parent partition requested by the VSC, in the child partitions. In other words: the VSP is how the VMs gains access to the physical devices on the parent.
IC does not require changes to the OS, and help to reduce the overhead of certain operating system functions such as disk access and memory management.

The Integration Components supports the following services:

1)      (IDE, NIC, SCSI, mouse, video) Synthetic devices
2)      Time Synchronization
3)      Data Exchange
4)      Volume Shadow Copy Service
5)      OS Shutdown
6)      Heartbeat

What if the IC is not installed?

VMs without IC installed (so called ‘legacy guests’) do not have the access to the VMBus or VSCs. In other words,  there is no support for synthetic devices. This affects performance, and will result in a software emulation of hardware device drivers in the operating system to the parent partition. Back to performance: VMs without IC installed, would perform at a much lower level than the VMs with IC installed. Software emulation of hardware devices may require thousands of instructions, compared to a few instructions directly in the hardware.

In addition: the IC is included in the distribution of Windows Server 2008 R2 and Windows 7, so there is no need to install the IC separately after the deployment in Hyper-V.


Olaf said...

Great Post!
But I think it is important to mention that there could be a need to install the ICs into Windows 7 and Windows2008R2 VMs.
There are no Hyper-V-Hotfixes for childs anymore, instead there are hotfixes for the parent which can bring in new versions of the ICs.
So if you want to have the latest and greatest Integration you should install the ICs after VM-OS-Installation.

Kristian Nese said...

Yes, it could be necessary to update the IC, but the IC itself is present in Win7 and 2008 R2, so they are able to communicate over the VMBus, and not as a legacy guest. But I agree that you would need to update the IC after install of hotfix or SP`s on the parent.