Virtual Desktop Infrastructure (VDI) is the modern version of the thin client movement of the 1990's. VDI essentially delivers desktop-as-a-service (DaaS), meaning end-users of desktops, laptops and notebooks can access a virtual set of servers that are allocated to providing client-side applications and services. Because these services are delivered over the corporate network, client management is simplified and ostensibly, end-user computing costs, support costs, licensing, and software maintenance expenses are all decreased.
In addition, proponents of VDI suggest that the approach is inherently more standardized and hence more reliable, available and secure because system images can be locked down, ‘templatized’ and easily replicated with control by an IT administrator.
Despite these appealing attributes, to date, VDI deployments have been confined to relatively narrow niches such as call centers, claims desks, government use cases and other environments where a critical mass of users is performing similar tasks consistently. Beyond these situations, organizations have struggled to realize the benefits of virtualized desktops largely because the end-user experience (from the standpoint of performance, functionality, graphics, etc.) has not lived up to that of the traditional Microsoft client model.
As a result, VDI to date has been seen as largely tactical by IT practitioners. At the January 25th, 2011 Wikibon Peer Incite Research Meeting, a panel of experts agreed that in order to become more of a strategic initiative, the notion of virtual desktop needs to evolve from a device-centric mentality to a data- and application-centric view. In other words, as users begin to access services from more devices (e.g. smartphones, tablets, etc.), VDI needs to allow access to user data and apps from any device, from anywhere at any time. It is the support of the mobile enterprise user that holds the most long-term potential for VDI and the name itself (Virtual Desktop) is increasingly outdated.
Where is VDI Prominent Today?
Much of VDI today is seen in industries such as financial services, education, medical/health (e.g. hospitals and clinics) care and government. For example, VDI is used for training students on how to use technology. In medicine, caregivers use tablets and card-scanning technology at kiosks allowing them to carry their virtual desktop, data, and applications with them as they move from patient to patient. U.S. federal government is another popular vertical due to the inherent consistency and standardization qualities of VDI.
A few years ago, VDI-related projects were initiated as very small pilots - e.g. 20 seat deployments. In 2010, the panelists saw more interest in 200 and 500 seat deployments, and today they are seeing much larger installations in the 1,000, 2,000, 5,000 and even 15,000 seat levels. Generally these deployments are occurring in situations where there is a high degree of user commonality from the standpoint application access, data type, and task performed.
Where's the Starting Point for Desktop Virtualization?
According to Michael Keen of Lakeside Software, a VDI specialist, users need to start by examining and understanding their data so they can make better decisions about how and where to deploy VDI. Keen calls this "decision acuity" and posits that lack of understanding of the data is one of the biggest pitfalls for users thinking about VDI. Keen suggests that the planning phase is crucial.
Glenda Canfield of VMware adds that it's critical to categorize users and understand their needs by groups. Many people think VDI can be deployed ubiquitously across the enterprise, but the fact is it can't. Different users and different 'tiers' of users will require different profiles, data and application access, and performance attributes so planning up front becomes even more critical for success. When it comes to user tiering, the panel suggests that a good way to tier is by user type or role - e.g. knowledge worker, task worker, etc.
The experts stressed that capturing and understanding data about the users was crucial to ensure successful deployments, and it was suggested that the collection of this data should be automated. Specifically, one person can manage an automated data collection task using automated tools over a period of 3-4 weeks versus perhaps as many as four people over a similar time period (or even longer) if attempted manually.
The bottom line is that from a planning perspective it's all about understanding the user experience and how to best replicate that in a virtual environment. If the user experience degrades, the project will fail. The panel suggest a classic analyze-->design-->build-->manage approach; with an understanding of the reality that desktop virtualization will be a subset of an overall virtualized infrastructure. Specifically, VDI will include a blend of:
- Virtual desktops,
- Physical desktops,
- Server-based computing,
- Application virtualization.
As such, as Jason Langone of MicroTech put forth, a key for users to understand is how to segment the overall virtual infrastructure and build out proper tiers of infrastructure (e.g. storage service levels for different user classes). Ultimately, the panel suggests that VDI becomes a hybridized component part of the overall virtualization strategy and should not be looked at in isolation.
Desktop Virtualization Cold Hard Facts
We performed some secondary research and found some statistics on VDI that are useful in setting context. Specifically, according to numerous surveys (e.g. Informationweek, The Register/Xiotech, ESG and a Falconstor-supplied survey):
- Roughly 68%-77% of organizations are either using, testing or strongly considering VDI deployments.
- Costs per VDI user range from $30-$40 to well over the traditional desktop average of $70-$90/user - depending on data protection level,
- Top five perceived benefits of VDI include: High availability, better utilization, simpler management, lower opex, and better security.
- Major barriers include difficulty in making a business case (whereas server virtualization is an easy business case), elongated time to value - i.e. it often requires project completion before benefit stream is realized, spotty user performance and functionality.
These trends resonated with the panel members and were clearly consistent with what they see in the field. The bottom line is that unlike server virtualization, desktop virtualization is much more nuanced and often has unclear ROI. Notably, in the military space the focus is on deploying quickly in an operational theater and security in the field. ROI and TCO are secondary concerns.
What are the Storage Constraints of VDI?
Rob Peglar of Xiotech joined the call and made some observations about storage, which they identified as one of the main drags:
- For every $1 spend on virtual desktop deployment, 3-10 is spent on storage.
- Most problems tend to be about I/O and storage.
- It's not just about how much storage capacity is needed but increasingly about how fast data needs to be accessed.
- Sizing virtual desktop installations (including remote desktops and mobile) is critical for storage - understanding access and I/O patterns is fundamental.
- Generally, individual desktop streams will be randomized in a VDI environment, which means poorly behaved storage with a mix of reads and writes.
- The key is to test at small scale (e.g. one dozen seats doing random access IO) and scale carefully.
- Boot storms are a particularly heinous barrier to adoption with a high Pareto I/O workload. A clean Windows 7 boot might take 150,000+ I/Os and a Windows 7 boot and login with lots of anti-virus and other background services might take 1M I/Os (with up to half of those writes).
- Questions must be answered including: What's the workload? Are you streaming to the desktop? Are you accessing remotely? What's the graphics workload over the network? Are users allowed to save to desktop? etc.
- Users will see a huge bottleneck effect where they should plan on anywhere between 10-30 iops per seat as a rule of thumb.
The bottom line according to Mr. Peglar is it's not the bytes that will kill you, it's the IOPs. And the standard of measurement is that users want their VDI experience to be no less than their existing desktop environment, and storage is a key component of that equation.
What About Mobile?
In anticipation of the VMware view client shipping, Jason Langone migrated to a pure iPad solution. His assessment - the solution, while cool, is extremely limited for mobile today. VDI must be primarily about delivering applications and there continues to be data access issues. Users are asking about iPads, netbooks, smartphones, and have the expectation that they will be able to access data and apps anywhere, anytime. The industry thus far is not delivering on this vision, but it's clearly the direction of VDI.
The bottom line is that for VDI to break out of its niche, the industry must put forth and deliver on a vision of user-centric computing proving data and application access to mobile devices. We are clearly in the early stages of that vision with perhaps 2-4 years of innovation required to deliver.
The panelists suggested users focus on 10 key areas:
- Plan, plan, plan!
- Understand user data and workloads.
- Understand end-users, their current experience, and how to replicate that.
- Understand access patterns and I/O requirements.
- Ensure you have the right network and storage infrastructure in place.
- Pilot small and make sure you can scale properly and make sure the end-user computing team is well-represented in the assessment process.
- Beware of virtual desktop sprawl - different classes of user will require different configurations.
- Understand these are not temporary solutions - plan for sustainability.
- Plan for operational readiness - e.g. how to manage and maintain; how to manage patches, etc.
- Make sure you have end user acceptance testing built into the project as a phase.
Also, the advice is to set SLA expectations conservatively - meeting current service levels at a minimum but not promising to vastly exceed current experiences.
Action Item: VDI implementations today are mainly tactical. While certain use cases are showing clear ROI, the vision of supporting myriad mobile devices and providing anytime, anywhere access to data and applications for all users is still years off. However gaining experience with desktop virtualization is critical to supporting next generation end-user computing environments and preparing for more transformative user experiences. VDI is becoming more stable and viable and 2011 is the year for users to ramp up expertise to learn how to leverage the concept for more strategic uses down the road.