Virtual Desktop Infrastructure (VDI) refers to a set of mainstream technologies and best practices that decouple operating systems, applications, and data from their underlying PC hardware in order to centrally manage and secure them within the data-center.

Instead of juggling thousands of static desktop images, IT can manage and update operating systems and applications once, from a single location, and deliver desktops and applications that are customized to meet the performance, security, and mobility requirements of their users.

Benefits

Follow Me Desktop

People can access their desktop from literally anywhere (e.g., different office spaces, personal laptop or tablet, or at home).

Security

Applications and data are physically secured in the data center, lessening the need for tools such as endpoint drive encryption.

Business Continuity

User endpoint devices are no longer single points of failure that prevent users from accessing their applications and data.

Lower Total Cost of Ownership

TCO reductions are estimated from 7% through 15% or more. However, each business case is unique.

Improved Productivity

Users are more productive when they can get their applications and data in more places.

Business Case

VDI is more difficult to cost-justify than server virtualization, but it can be done. Server virtualization reduces the amount of equipment in the data center, whereas with virtual desktops, physical hardware must be added to the data center. The additional hardware for virtual desktops may be an issue with data centers struggling to provide enough power and cooling for what they already have. Desktop virtualization does not offer the rapid ROI that has made server virtualization a 'no-brainer' business decision. Instead, the business case is built on less tangible results, such as tighter security and increased workforce mobility. Properly architected Server Hosted Virtual Desktops, however, can result in a significant reduction in desktop support costs.

Several techniques can help keep capital expenditures (CAPEX) in check:

• Anticipate the average Server Hosted Virtual Desktop CAPEX to be 1.4 - 1.7 times the cost of a physical desktop; although 1.0 - 1.4 times is achievable
• Centralize desktop images; limit the number of dedicated virtual desktop images
• Re-purpose physical desktops as thin clients
• Evaluate the feasibility of System on a Chip (SoC)/ARM-based thin clients (<$200 retail)
• Beware hidden costs (personalization, print roaming, network and storage upgrades)

Project Roadmap

ITD is interested in having one additional agency participate in the VDI proof of concept. After it concludes, stakeholders will be identified to participate in the pilot implementation; this entails a funding commitment.

Storage Considerations

Numerous storage considerations heavily influence the costs, scalability, management, and user experience. This starts with the configuration of the virtual desktop's virtual hard-disk architecture. The persistent storage model results in each user having a dedicated virtual desktop with dedicated storage, similar to the storage architecture of the traditional desktop. The nonpersistent model, on the other hand, allows virtual desktops to boot from a shared read-only master (that is, 'golden') image.

Persistent storage is the easiest solution to deploy, but it can result in significantly higher back-end storage costs because every user is assigned a dedicated virtual desktop image. It is simple to manage because management is nearly identical to that of the physical desktop. Users who require customization of their desktop environment are often assigned virtual desktops with persistent storage.

Nonpersistent storage involves allowing multiple users and virtual desktops to leverage a shared read-only image. That approach sounds great on paper and works well in some use cases (for example, task workers who require no modification to their desktop environment). However, the solution has trouble supporting knowledge workers without the aid of persistent personalization software.

Client Devices

In the typical VDI deployment, organizations choose between repurposing physical PCs and deploying new thin or zero clients. Repurposing physical PCs to behave like thin clients is a common strategy for reducing the initial capex required to deploy virtual desktops. This approach also allows organizations to buy themselves some time to wait out further maturity and innovations coming to thin- and zero-client endpoints. Furthermore, the organization can reduce risk by limiting its financial investment in a first generation VDI project.

Complimenting Technologies

Several other technologies complement virtual desktops as part of the modern user-centric application and data delivery approaches.

• Server-based computing
• Application virtualization
• Persistent personalization
• Cloud software and data services
• Workspace aggregator