Desktop Virtualization Strategy:
Seven Traps to Avoid
GlassHouse Technologies Whitepaper
Desktop Virtualization: Don’t Make these Simple Mistakes
The buzz and activity around desktop virtualization today is immense. Why areorganizations interested in desktop virtualization and what are the benefits it offers? Our customers cite numerous drivers; here are a few of the more popular reasons that
organizations embark on such a significant and potentially disruptive initiative.
Desktop Management Efficiencies
More efficient management of the desktop ‐ i.e. operating system upgrades, provision new applications/desktops, deploy updates and patches – can translate into more efficient management of budgets. According to IDC, for every $1 spent on desktop hardware, companies currently spend $3 to manage that hardware. Workspace Mobility Enterprises want to provide a secure solution for end‐users to access company applications and data from their home offices or while on the road, allowing for greater work efficiency and employee satisfaction. Workspace Continuity Workspace Continutiy provides a cost effective disaster recovery solution for your virtualized desktop environment. Businesses spend significant time and money protecting their data center assets but seldom consider the desktop or access point when planning for Disaster Recovery. At best they may have access to a few workstations at the DR site or a limited remote access solution that users are not familiar with. Virtualizing the desktop simplifies the process of Disaster Recovery/Business Continuity for the workspace. Because the desktops reside in the data center, they can be easily replicated to the DR site just like the rest of your data. Users can then access the virtualized desktop from any remote location that has connectivity to the DR site once the data center applications have been recovered. The solution will also be available during an event that doesn’t knock out the data center but still prevents users from coming to work such as a pandemic, terrorist threat, weather related event or geo‐political condition.
Windows 7 Migrations / Application Virtualization
Enterprises can minimize disruption to the business by combining initiatives. If you have been planning to migrate your end users to Windows 7, but you know there is a desktop virtualization initiative on the horizon, you could be wondering if they should be combined. The short answer is yes. Both initiatives are potentially disruptive to end‐ users and rather than making two significant changes to the desktop these activities can be combined. Use workspace virtualization to accelerate your migration to Windows 7 Andy Cohen, Workspace Senior Consultant
and leverage application virtualization technologies to efficiently deliver applications to this new environment.
Migration to Cloud Services
When moving to the cloud, test cloud services with low‐impact workloads first. Some desktop services will be good candidates for this; however careful planning is required to ensure an ideal user experience and solid security.
The Differences between Server Virtualization and
Desktop Virtualization
I’ve already virtualized my servers, isn’t this just the next step?
Before you jump in, think clearly about this statement. Desktop and server virtualization are different. Desktop virtualization is not just about shared resources in the data center like it is with server virtualization. Desktop numbers will scale much more quickly than servers and other factors ‐ like WAN, LAN, and storage ‐ can become deal‐breakers. Some of the other aspects you need to consider when moving forward with desktop virtualization are: Cost Implications The ROI for server virtualization is easily identifiable and the business case can be clearly justified on capital expenditure savings. The only consideration is, “How quickly can I get this done and start saving money?” Desktop virtualization cost savings can take longer to recognize. You may find that the capital cost of implementing a desktop solution could cost close to, or even more than, a traditional desktop solution. Significant cost benefits can be seen over the long term in operational expenditure savings but these should be fully understood and explained to the business before embarking on a project. Workload Differences The degree to which virtual server and virtual desktop workloads differ cannot be underestimated. In contrast to server workloads, desktop workloads tend to have periods of synchronous burst activity that tend to generate large fluctuations away from the average utilization. Too often, server teams unacquainted with the degree of workload collusion generated by desktop users and desktop maintenance processes are in charge of designing the desktop solution and estimating the necessary shared resources. The result can be hardware resources capable of accommodating average levels but completely under‐provisioned for the peak workloads that typically present themselves in virtualized desktop. The result is large injections of latency into the user experience across all the major areas such as CPU, storage, network performance, etc. Having a good grasp on the statistics behind your virtualized desktop workloads is the key to proper infrastructure provisioning and paramount for successful SLA‐based management of the end user experience.
Workloads Basics: Server vs. Desktop
What are the ‘Traps’ when deploying desktop
virtualization?
When making the decision to move ahead with a desktop virtualization initiative, there are several key issues you need to recognize and manage for a successful deployment. Consideration and understanding of these issues now can streamline the process and accelerate your realization of benefits and potential ROI. Here are the seven top issues to explore prior to a desktop virtualization deployment:1.
Use Cases and User Profiles for the Workspace Environment
What do we mean by the “workspace”?
The “Workspace” is where users interact with the business processes, systems, and customers that drive the business. This includes traditional desktop, VDI, terminal services, application virtualization, etc. The workspace is about delivering applications and data to users. Server Desktop Diversity on Cluster Homogeneous on Cluster Peaks randomized across Apps Synchronous Peaks I/O loads are chiefly App driven I/O loads are often User driven Maintenance workloads are manual or targeted. Maintenance workloads are often synchronous on many machines Batch oriented workloads Real‐Time Workloads Performance Fluctuations have low to moderate visibility Performance fluctuations have high visibility Low to Moderate Workload Volatility ( peak < 3x average) High Workload Volatility (peak > 10x average)
According to the IDC,
companies often adopt a
‘one size fits all’ approach to
the technology – one that
wasn’t always appropriate.
“There are different types of
desktop virtualization,
ranging from server‐based
computing, which would be
suitable for simple
applications or for task
worker, VDI for knowledge
workers and consolidated
clients, blade PCs, suitable
Pros
• Low performance risk • Good user experience • Low Impact on Data Center
Cons
• High Support Costs • Data Security issues • OS Upgrades Difficult • Application Management Workspace Virtualization Workspace Virtualization Organizations should consider all the technology options to determine the best architecture for their workspace needs. This begins by profiling your users and applications to determine the optimal desktop solution(s). Profiling starts by understanding the applications they use and how they use them. From there you can design the different architectures that will be appropriate for the different user profiles in your organization. Understanding the business needs and user requirements will then drive the appropriate workspace technologies. Designing an environment to support the various requirements can result in the definition of several use cases and profiles, each requiring a different solution where the application and its service level agreements define the delivery method. The appropriate workspace technologies are then applied to the different user profiles depending on their needs. While it may sound inefficient to deploy multiple architectures across your environment, the design can create efficiencies by leveraging technologies that are common across the different user profiles. For example a “general task worker” user profile may be appropriate for a stateless VDI architecture. This means that users share a common pool of virtual desktops resulting in a reduced storage footprint and increased operational efficiency. A “power user” who needs to install their own applications, may require a hybrid VDI design or even a physical desktop. But both users can take advantage of a common application virtualization infrastructure which allows for a greater degree of application control and distribution.
Power
User Trader / Analyst Developer / IT Support PurposeBuilt VDI ApplicationNon-Core Remote Worker Mobile Worker Knowledge Worker Task Worker Description
Generally a single-task or multi-task worker with a well-defined set of applications and a repetitive job function. May involve more than one application, but is focused on completing a single task. In a stateless VDI design users share a common pool of virtual desktops. This allows for a reduced storage footprint and also decreases the management and support requirements of the virtual desktop solution. Since users share a virtual desk image they cannot make persistent changes to them. This means that the common image reverts back to it’s “golden” state each time the desktop is rebooted.
Reference Architecture Stateless VDI
Design Considerations Application Virtualization: Allows for a greater degree of application
control and distribution, reduces application conflicts through isolation, good use in a BC/DR scenario where users may not be at their normal production workspace.
Citrix XenApp: Integrates XenApp based applications on top of virtual
desktops to centralize applications in the datacenter and reduce the number of applications to be deployed to physical and virtual workstations.
VM Hosted Applications: Purpose built virtual desktops to host
specific applications that require either a higher degree of isolation or compute resources.
Roaming Profiles: Used primarily in stateless VDI solutions to allow
users to save customizations made to their local profile
User Types
Call Centers, Bank Teller, Mortgage Processing, Order Entry
Solution Requirements:
Type 1 Hypervisor: vSphere, XenServer, Hyper-V Connection Broker: View, XenDesktop, vWorkspace, Leostream Streaming Images: Composer, XenDesktop, NetApp FlexClones App Virtualization: ThinApp, XenApp, App-V, Altiris SVS, Install Free Roaming Profiles:RTO vProfiles, UPM, AppSense
Possible Add-ons:
Hybrid Clients
Virtualized Applications
Citrix XenApp
Design Alternatives
Server based computing (Terminal Services) / Task Worker
Persistent VDI / Knowledge worker
Power
User Trader / Analyst Developer / IT Support PurposeBuilt VDI ApplicationNon-Core Rem ote Worker Mobile Worker Knowledge Worker Task Worker Description
A “Hybrid Workspace” allows local and rem ote applications to be com bined into a single desktop experience. Local applications benefit from a dedicated processor and zero-latency graphic response tim es. They can be pre-installed onto the local “im age” or can be delivered on dem and from an application virtualization stream ing source. Rem ote applications can be presented via Web-based applications that can use the local browser, or through “thin client” technologies such as XenApp and VM hosted applications.
Reference Architecture Hybrid VDI
Design Considerations Application Virtualization: Allows for a greater degree of application
control and distribution, reduces application conflicts through isolation, good use in a BC/DR scenario where users m ay not be at their norm al production workspace.
Citrix XenApp: Integrates XenApp based applications on top of virtual
desktops to centralize applications in the datacenter and reduce the num ber of applications to be deployed to physical and virtual workstations.
VM Hosted Applications: Purpose built virtual desktops to host
specific applications that require either a higher degree of isolation or com pute resources.
Roaming Profiles: Used prim arily in stateless VDI solutions to allow
users to save customizations m ade to their local profile
User Types
Engineers, audio /video intensive applications, graphics intensive applications, scientific researchers
Solution Requirements:
Type 1 Hypervisor: vSphere, XenServer, Hyper-V Connection Broker: View, XenDesktop, vWorkspace, Leostream
Possible Add-ons:
Hybrid Clients
Virtualized Applications
Citrix XenApp
Design Alternatives
Client Side Hypervisor
With the reference architectures for different user profiles created, you can create a workflow and decision tree to determine what architecture a given user would fall into. Process begins with a user survey being completed by the Customer or selected group of end‐users. Data collected during the survey process is used to answer the questions and decision points in the process workflow Visio document.
Design – Persistent “VDI”
2.
Are my reasons for virtualizing my desktop valid?There is no doubt that there are a plethora of reasons for moving to desktop virtualization, but are these reasons valid and are they aligned to potential designs? For example, my driver is increased user experience but I selected a vendor’s solution that will not perform well over high latency links. I also want to migrate my call center from Citrix to VDI to reduce application conflicts and regression testing. Is this really the right approach or should I look to virtualize my applications in my Citrix environment instead? What is the best way to figure this out? Start with your requirements and challenges and not products. • Obtain a deep understanding of your business challenges, pain points, and issues • Clearly define the business, as well as technical drivers
Business Benefit Technology Benefit
Reduction of overall desktop
support cost
Centralized Management – Standardized desktops, always connected, and powered on in the data center facilitating
management
Reduction of Application
development, testing &
deployment cost
Robust application delivery and support regardless of
location
Reduction of HW, OS &
maintenance cost with maximize
uptime
Resource Optimization – Optimize server resources through dynamic management for virtual desktops
Strict adherence to legal &
regulatory requirements
Secure Environment / Isolation – Secure sensitive content within the data center with complete user isolation
Global virtual workspace, little or
no cost of user or office move
Complete Desktop Access ‐ Remote access to full desktop environments from anywhere in the world via an internet connected web browser
Reduction of legacy application
Management cost
“0” application conflict
Business Continuity Service‐Orientation – Deliver desktops as an enterprise service
Drivers for desktop virtualization
3.
Anticipating “Unanticipated” CostsOrganizations should be careful to determine ALL of the costs and benefits of implementing a desktop virtualization solution. Because the solution may contain components from many different vendors, it’s often difficult to get one final cost without overlooking something. The solution may also change licensing and support/maintenance agreements you already have with your vendors. For example, one of the less‐known licensing implications of desktop virtualization is the Microsoft licensing for the virtualized desktop operating system (OS). Just like the physical desktop, customers need to be correctly licensed for their VDI environments. Licensing policies from Microsoft have been adjusting to the increased adoption of desktop virtualization solutions. As of July 1, 2010, customers that have devices already covered with Windows Client Software Assurance (SA) can now use those devices to access virtual desktops in the data center at no extra charge. Customers that intend to use devices that do not qualify for Windows Client SA, such as thin clients, require a new license called Windows Virtual Desktop Access or Windows VDA. This is a significant change to Microsoft client licensing and can have a substantial impact on the cost of deploying a virtual desktop solution:
Additionally, by implementing a desktop virtualization solution, customers can replace standard desktops with low‐powered thin client devices. This can have a significant impact on power and cooling costs. The thin clients, typically, also have a longer lifespan than the average desktop computer. A financial analysis will show considerable power and cooling savings, but be sure to factor into your calculations that much of the power and cooling costs have been shifted from the office space back to the data center. All those virtual desktops may require a significant amount of server power to run. The servers in the data center will need to be refreshed every couple of years as well. Finally – make sure your solution can spin down the servers during the night to further increase power savings.
4.
Have I designed a solution to properly address the applications my users utilize?Application functionality can drive the technology direction of your desktop virtualization initiative. Just like user profiles, applications should also be assessed to determine the most appropriate delivery mechanism for a particular application to a particular user.
Review the current application infrastructure and processes
In order to accurately create plans that build upon the existing application
deployment infrastructures and add to their functionally, it is critical to have a clear and full understanding of the technology solutions that are already in place. These technologies will often serve as the foundation for the new application provisioning
and delivery model, and as such, hold a significant role in the entire planning and design process. The review should also include any recent, current, or upcoming plans to enhance or upgrade the provisioning and delivery infrastructures.
Create processes that make up an application evaluation system
Develop a framework for the assessment, evaluation, and decision criteria used to determine the delivery mechanisms for each application. Processes developed typically would include: • Processes and tools to be utilized to properly inventory the applications that are currently in production o Understanding of the performance characteristics of each application o Network dependency mapping, showing the connections that each application requires to datacenter resources • Processes and tools to be utilized in the evaluation of the applications • Recommendations for tracking mechanisms to maintain a database of the applications and their status in the environment • Automation tools to be used to simplify the process of the evaluation • Processes and procedures to be used to evaluate the characteristics of the applications that are not captured by an initial automation process, such as: o Application behavior and multi‐system dependency o Inter‐application dependencies at the system and functional levels o Security or compliance requirements at the application level o User, hardware, or networking requirements o Application performance characteristics and requirements • Cultural and end‐user experience bias
Document the application evaluation framework
The result of the exercise above is a series of documents and tools for a reusable “Decision tree” framework in which each application can be evaluated against a defined set of criteria that takes into consideration the organization’s infrastructure, end users requirements , and requirements of the actual application. The decision tree will be used to quickly and easily determine the most appropriate methods of provisioning and deploying each application.
5.
What is the impact to storage from my initiative? Storage is often overlooked when large initiatives are being launched in IT. It’s always the after‐thought. The risk to that after‐thought, however, is significant to the business. If you haven’t thought through the impact virtualizing your desktops can have on your storage environment, you are risking: Cost The cost of storage needs to be carefully evaluated when architecting your desktop virtualization initiative. Consider that your organization may have thousands of physical desktops, all running with low cost disk drives. Moving those desktops to the data center, where they will likely be hosted on data center class shared storage devices that are typically much more expensive. One thousand desktop images at 20GB each is about 20TB of storage. As you’ll see below – virtual desktops often require as high, if not higher, performance storage than servers, so don’t just think you can place these desktops on low cost SATA drives. Storage optimization is the use of “Gold” OS images to decrease storage overhead by allowing you to provision a single common image to all users. De‐Duplication is also a strategy than can be implemented to mitigate this problem. Storage optimization and/or de‐duplication can help reduce the storage footprint of your initiative but the implications of implementing it can have significant impacts on your design and the support/operations of the solution. Furthermore, there are many industry options for solving this problem so architects should properly weigh the pros and cons of each before deciding on a solution. I/O requirements As discussed above, the workload patterns of desktops and servers are very different. This is especially significant when it comes to storage performance. When you aggregate the workloads of many desktops on the same storage infrastructure you may notice serious performance impacts. Take for instance, that many environments run automated batch jobs such as virus scans on all their workstations at the same time. This storm of I/O from thousands of desktops hits the storage infrastructure all at the same time and can bring an infrastructure to its needs. Even the simple act of boot‐up and logging‐in in the morning can have an impact. Fortunately, there are strategies and solutions available to mitigate this problem. Here are a few tips to consider when designing your solution:Create storage design options to minimize burden on shared storage and reduce risk during periods of burst activity.
Type Description Pro Con
Local
Storage
Use local disk Reduce load on shared
storage
Limited IOPS per
host
Upstream
Cache
VA for IOPS
offload
80% less IOPS go back
to NAS
Memory impact,
license fees
Tiered
Storage
SSD on NAS Great for Gold disk.
Simple
NAS Engine still a
bottleneck
Dispersal
Storage
Cluster of
Local Disks
Resilient, Cheap, Fast Nascent
Technology
6.
Network latency will impact the users’ desktop experience?
One major use‐case of desktop virtualization is supporting remote and home users. Understanding where your users are and the network quality and latency are huge factors in determining an appropriate solution.
We’ve come a long way in our ability to provide a rich user experience for remote users but we still have to account for the physical distance a user is from the data center. This is another area where understanding your application will help determine the best technology to deliver them with. Where applications are just not suitable for remote display you may choose to implement a “Hybrid Workspace” where locally and remotely executed applications can be combined into a single “desktop”. The hybrid workspace combines the best of local application execution with the benefits of remote presentation of applications.
7.
Prepare for impact...The desktop, including the user experience, perception, functionality, and reliability is too important to “mess up”. A poorly executed desktop virtualization implementation can cause users to reject the solution and not only cause you to re‐architect but users will be much more resistant as you try to implement the next solution. Many desktop virtualization projects fail before they even begin. The promises of unrealistic returns on investments and reductions in capital and operational expenses have companies struggling to implement a successful desktop virtualization solution. In addition, incomplete vendor solutions and the failure to properly assess end user requirements can cause rejection of the solution and stall a desktop virtualization initiative. Consider the following methodology to help reduce risk while evaluating complex projects such as desktop virtualization: • Start with IT and end‐user requirements and challenges…not products o Obtain a deep understanding of the challenges, pain points, and issues o Clearly define the business, as well as technical drivers • Map the requirements to the appropriate products and technologies o Analyze the drivers and requirements and apply priorities o Independent review and recommendations of products, solutions, and practices designed to meet the defined requirements • Architecture and design to integrate into the existing environment o Implement and test the solution o Create rollout plan and detailed financial analysis o Perform test and pilot phases that are critical to overall success • Document and train o Document the Pilot to Production environment o Provide administrator and end user knowledge transfer Conclusion Desktop virtualization can provide significant benefits in terms of operational efficiencies, business agility, security and Disaster Recovery but a design must be well thought out and take into account the needs of the business. Review the considerations above and make sure you are properly assessing them to ensure a successful solution. Other significant factors to consider include the challenge of designing your solution to scale, and the costs and efforts associated with components of your solution such as
application virtualization and profile virtualization and the security implications of your solution. While a desktop virtualization solution may seem like a project for the desktop team, the considerations above as well as many others require careful coordination between many groups within your organization. As the desktop moves into the data center we see that the lines of responsibility between different groups are becoming blurred and the teams are being asked to work together to solve the business problems. Make sure you have buy‐in and executive sponsorship from those who can tie into the many different groups and make decisions that crosses boundaries.