Dynamic Memory worked by configuring a starting amount of memory and a
maximum amount of memory. Hyper-V would then monitor the actual amount of
memory being used within the virtual machine by processes via the integration
services. If the amount of available memory dropped below a certain buffer threshold,
additional memory was added to the virtual machine if it was physically available. If a
virtual machine no longer needed all of its memory, some was reclaimed for use with
other virtual machines. This enabled Hyper-V to achieve great optimization of VM
memory and maximize the number of virtual machines that could run on a host.
The other new technology in Service Pack 1 was RemoteFX, based on technologies
obtained through the Calista Technologies acquisition. The RemoteFX technology was
focused on Virtual Desktop Infrastructure (VDI) deployments running on Hyper-V
and making the VDI experience as rich as possible no matter the capabilities of the
client device. RemoteFX consisted of three technologies to offer this rich capability:
The first was the ability to virtualize a GPU (Graphical Processing Unit) in the
Hyper-V server and then assign virtual GPUs to virtual machines. This works in a
similar way to how CPUs are carved up between virtual machines. Once a virtual
machine was assigned a vGPU, the OS within that VM could perform native
DirectX processing using the GPU, allowing graphically rich applications to run,
such as videoconferencing, Silverlight and Flash applications, and any DirectX
application. As a demonstration, I installed Halo 2 in a RemoteFX-enabled virtual
machine and played it over the network; you can see this at
http://youtu.be/CYiLGxfZRTA. Without RemoteFX, some types of media playback
would depend on the capability of the client machine, and certainly any application
that required DirectX would not run. The key item is that all the graphical
rendering is on the Hyper-V host’s GPU and not on the local client.
The second technology was related to the rich graphical capability and was an
updated codec that was used to compress and uncompress the screen updates over
the network.
The final technology enabled USB device redirection at a port level. Typically, with
Remote Desktop Protocol (RDP), certain types of devices could be used in remote
sessions, such as a keyboard, a mouse, a printer, and some devices with an inbox
such as a scanner. However, many other types of devices and multifunction devices
would not work. RemoteFX USB redirection enabled any USB device to be used in
a remote session by redirecting at a USB port level all USB request blocks (URBs).Note that the last two components of RemoteFX, the codec and USB redirection, are
not Hyper-V features but rather updates to RDP. I cover them because they are part of
the RemoteFX feature family and complete the remote client experience.
The combination of Dynamic Memory and RemoteFX made Hyper-V a powerful
platform for VDI solutions, and Dynamic Memory on its own was useful for most
server virtual machines as well.