Hyper-V's integration components (also known as enlightenments
or integration services
) can be thought of as a set of device drivers. When installed, they offer the best possible performance for your virtual machine. They can even allow you to use additional types of virtual devices that are not otherwise available in an emulated virtual machine.
Integration components are more than just drivers. They also provide a set of services that allow the virtual machine to integrate with the Hyper-V host server. For example, you can synchronize the clock of the virtual machine with the physical clock of a Hyper-V host machine. You can conﬁgure a virtual machine to automatically start after the host machine starts, specify how long to wait, and also specify what should happen to the virtual machine when the host powers down (shut down or save state). Microsoft provides integration components for a large set of supported operating systems, which is shown in Table 2.1 later in this chapter (when we discuss virtual processors). You can install integration components using Virtual Machine Manager or the Hyper-V console. Windows 7 and Windows Server 2008 R2 include integration components by default. However, the correct integration components version is dictated by the version of the operating system that is used for the Hyper-V parent partition or host operating system
. For example, a Windows Server 2008 R2 host will have older integration components than those on a Windows Server 2008 R2 with Service Pack 1 host. You should always install the latest version in your virtual machines that your host will support.
The one piece of information that is a must to remember is this: always install the integration components in your virtual machine. There have been too many cases where requests for help have been resolved very quickly by installing the absent integration components in the virtual machine's operating system. Virtual Machine Manager 2008 R2 will take care of this for you when you deploy new virtual machines or perform a migration with the virtual machine powered down. (Source