Desktops. Personal Session Desktops behave in a similar fashion to personal VDI
desktops except that the operating system running in the VM assigned to a user is
Windows Server 2016 configured as a session host and the user optionally has
administrative rights. The use of a server OS is beneficial primarily when a VDI level
of isolation is required but the licensing restrictions of Windows clients prohibit a
typical VDI deployment, such as running in a public cloud (where Windows client
operating systems cannot be licensed), or when an agent cannot be deployed on the
virtualization hosts (which is required for VDI and not possible in a public cloud). At
times, a server OS might be a better fit for user scenarios, such as for certain
developers.
It won’t come as any surprise to you that the vendors who push VDI as the best
solution for every scenario are those who don’t have a session virtualization solution,
so VDI is their only way to expand into the desktop market. Vendors who have both
VDI and session virtualization, such as Microsoft and Citrix, take a more balanced
approach. I give more guidance later in this chapter on when to use each type of
desktop virtualization, because most organizations need some of each.
Whether session virtualization or VDI is used, the end result is virtualization of the
desktop, or simply virtual desktops. So why do people even want these virtual desktop
solutions? The following are some of the most common reasons:
Disaster-recovery situations in which the normal work office for users is not
available because of a disaster or for some other reason. Say a huge blizzard
prevents workers from leaving their homes. With a virtual desktop environment
available, users can connect to the virtual desktop, and their complete desktop
environment is available.
Contract users with their own computers who need a corporate desktop
environment. Rather than rebuild their computers, just give them access to a
desktop in the corporate virtual desktop environment.
Users who need to use many devices and require a consistent desktop experience.
This could include users who use shared devices such as in hospital environments.
High-security situations in which data cannot leave the datacenter and the user’s
desktop must also be housed in the datacenter. It’s not practical to sit users in the
actual datacenter, so remotely accessing the desktop that is colocated in the
datacenter is the best of both worlds.
Certain applications that access huge amounts of data that is stored in the
datacenter. Sending the data over the network may be impractical or give poor
performance, so hosting the desktop in the datacenter with the application
effectively running on the same local network gives great performance.
Critical desktops that need high resilience. Consider that with virtual desktops, the
desktop operating system is running on server hardware, which means server-
class performance and server-class high availability and redundancy including
RAID-based storage.