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Sizing and Best Practices for Deploying VMware View 4.5
on VMware vSphere 4.1 with Dell EqualLogic Storage
2
2 Virtual Desktop Infrastructures
Desktop virtualization is emerging as an important strategy for organizations seeking to reduce the
cost and complexity of managing an expanding variety of client desktops, laptops, netbooks, and
mobile handheld devices. In a VMware View based VDI environment, user desktops are hosted as
virtual machines in a centralized infrastructure. The user interface to the desktop virtual machine is
transmitted over a network to an end-user’s client device.
2.1 Benefits of VDI
In a VDI environment all desktops are centrally managed. Each desktop can be derived from a small
number of “gold” base images that system administrators can easily and efficiently manage. When
patches and upgrades are applied to a base image, the changes are automatically propagated to all
user desktops derived from that base image. This eliminates any issues with application and device
compatibility. Workstation provisioning is simpler and faster than in traditional desktop PC
environments. User workloads can be (automatically) moved between resource pools in the
centralized infrastructure during demand spikes. Using a VDI delivery model, IT organizations can
execute smoother transitions during upgrades or new operating systems deployment periods.
The centralized desktop management model of VDI lends itself to easier data protection. This is
because, from a storage point of view, a VDI desktop environment is similar to any enterprise
application running in a data center. Security and compliance are other areas where VDI solutions
create advantages over the traditional desktop PC computing model. In a VDI environment, it is
possible to ensure that no data resides on end-point devices. The enterprise security risks that are
introduced by end users locally installing applications can be significantly reduced by using a tightly-
controlled centrally-managed VDI environment.
2.2 Storage Requirements for VDI
A VDI deployment must be carefully designed to ensure that it delivers the performance and scalability
needed to support large scale client computing requirements inside an enterprise. When migrating to
a VDI model, a lot of the components—storage, processors, memory, and networking—that supported
the traditional desktop PCs are moved to a centralized data center.
A VDI deployment can place high capacity and performance demands on the underlying storage
platform. For example, consolidation of large amounts of inexpensive stand-alone desktop storage
into a centralized infrastructure translates into capacity requirements that the shared storage used by
the VDI solution will need to meet. Performance considerations include how to estimate the
aggregate volume of I/O operations per second (IOPS) generated by basic desktop client operations
(system boot, logon, logoff, and application usage patterns) that VDI solution will need to support.
IOPS requirements will change based on user profiles. The application I/O profile generated by a
typical task worker will differ significantly from that created by a knowledge worker or power user. I/O
“storm” events can be caused by large amount of simultaneous activity, such as morning logons and
afternoon logoffs. The events can cause I/O spikes that place high performance demands on the
storage infrastructure.