Figure 11.2 VDI solution in action
A VDI deployment has two modes: pooled and personal desktops. Most VDI
deployments will leverage a pooled deployment for the majority of VDI users. In a
pooled VDI configuration, numerous virtual machines running the client OS are
grouped into a pool. As a user connects, the user is automatically assigned one of the
VMs not currently in use. Once the user has logged off, the VM is placed back into the
pool. Because a user potentially (and probably) gets a different VM each time they
connect, it is essential that you have solutions to maintain the user’s profile and data
between logons. After a user logs out, the VM in the pool is reset to a clean state in
case anything was changed by the previous user.
Pooled desktops should be the default for all users, but certain users might need the
same client OS instance every time they connect. Maybe they are modifying the OS in
some way, or perhaps they have an application that needs to be installed because it
can’t be virtualized. Whatever the reason, you have the capability to statically assign a
VM to a particular user so that they always get the same client OS. This is known as a
personal desktop.
A pooled desktop environment allows a gold image to be used as the template for all
VMs in the pool. Because no user state is stored in the VMs in the pool, there is no
need to patch or maintain those VMs. The only maintenance required is to patch and
manage the gold image, which will then refresh all VMs in the pool. This is not
possible for a personal desktop, because the VM is maintained for the specific user
between logons and therefore must be patched just like a regular desktop. It also may
lay dormant if not used by the user but will still consume resources. It is therefore far
more preferable to use pooled VMs over personal VMs when you use VDI.
Windows Server 2016 introduces a new type of VDI deployment: Personal Session