A Practical Guide to VDI Change Management
Part 5: Building Resilient VDI Infrastructures
So far we've covered a lot about the speed and sensitivities required around VDI Change Management (see our previous blogs HERE). In this article, we discuss how you can ensure your VDI Environments are robust resilient, and help you avoid problems.
IT service management emphasizes reliability and resilience
As discussed in chapter 1, ITIL provides a comprehensive description of practices that are part of the IT service management (ITSM) function. This function is crucial in every large organization as it aligns the IT service operation with the business needs of an organization. ITIL covers 5 phases: Strategy, Design, Transition, Operation, and Continuous Improvement.
In the Design phase the following service management processes are discussed (source: Wikipedia):
- Design coordination
- Service catalogue management
- Service-level management
- Availability management
- Capacity management
- IT service continuity management
- Security management
- Supplier management
When we seek to design and build resilient VDI infrastructures that will provide and guarantee an optimal end-user experience and application performance to the organization, ITIL gives useful recommendations for managing availability, capacity, and service continuity.
Availability management covers the ability of an IT function to perform at an agreed level over time. This is often documented as a Service Level Agreement (SLA). Aspects such as reliability (does it work as required) and resilience (can it weather changes/failures) are key components of availability management.
Capacity management covers the optimal balance between business needs and IT services. This includes activities such as IT capacity planning and IT infrastructure sizing.
Service continuity management
Service continuity management is about making sure IT services can continue to deliver as expected, despite a growing and accelerating flow of (planned) changes or possible incidents. The focus of this discipline is not only on recovery measures, but more and more about pro-active activities, because preventing interruptions is clearly the most effective way to contribute to better business continuity.
How testing helps to design and build better VDI environments
Compare VDI performance to fat-client performance
When trying to decide if a virtual desktop solution is an option to augment or replace your fat-client desktop environment, the ‘same or better’ end-user experience will most often be the decision-making factor. Objective load testing of the old and new environment is the preferred way for vendors, system integrators and enterprises, and must be a part of every well-executed proof of concept.
A large organization in Europe used performance testing to establish a baseline measurement for their VDI environment. When benchmarking different hardware options, the one that came closest to the fat-client baseline was chosen, which not only helped user acceptance but also helped to prevent subjective discussions about the performance of the new system.
Benchmarking different virtual desktop infrastructure options
When moving to a virtual desktop solution, enterprises must choose between different infrastructure options including the solutions of Citrix, VMware or Microsoft, as well as different hardware options like hyperconverged infrastructure, server, storage and GPUs. Objective load testing is the best way to benchmark the different infrastructure options under consideration and to make fact-based decisions.
A large hospital organization in Europe challenged the vendor requirements of two separate server environments for their XenDesktop VDIs and their Electronic Patient Record application on XenApp. Login VSI was used to verify this option against the all-in-1 system option. With a just-as-good load test result on both performance and scalability, the hospital saved 1.3 million$ on hardware while providing their users with the same user-experience and application performance.
Sizing, scaling and tuning the new virtual desktop infrastructure
The correct scaling and sizing of the virtual desktop infrastructure is important in every VDI project. Too little infrastructure will obviously cause problems with performance when systems are heavily used. Too much infrastructure will cause unnecessary spending in hardware purchase and maintenance, as well as wasting energy cost and datacenter space. Objective load testing is used by vendors, system integrators and especially enterprise organizations to correctly size and scale Citrix XenDesktop, Citrix XenApp, VMware Horizon View and Microsoft RDS infrastructures.
A large healthcare organization in the USA migrated to a new version of Epic using Citrix software on a new Nutanix hardware environment. After installation, based on vendors best practices, the environment could support 2,900 users. After some initial doubts about the performance, Login VSI was used to tune and optimize the entire environment, which increased the density to 4,000 users on the same environment with the same performance. Using standard TCO numbers this represents a monetary value of $3,000,000.
Pre-production (stress) testing
To safely move a new virtual desktop environment into production, it is advised to perform a (virtual) full-scale load test of the production system. Any risk of failure may be unacceptable, especially when business critical applications are involved. Objective load testing is used by smart vendors, smart system integrators and prudent enterprises to load and stress-test virtual desktop infrastructures before they go into production. These tests also indicate the resilience of the system to weather logon storms and other usage peaks.
A large organization in the USA pre-tested their new application in a VDI environment before going into production. During the tests serious failures occurred that were not detected with the original extrapolated tests with smaller loads. Testing prevented a significant loss of business in this case.
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About the company Login VSI
The company Login VSI provides end-user performance insights for virtualized desktop and server-based computing environments. Enterprise IT departments use flagship product Login VSI (for load testing) and Login PI (for continuity testing) in all phases of their virtual desktop deployment—from planning to deployment to change management—to build and safeguard a good performance, a high availability, and (as a result) a good and consistent end-user experience. For more information about Login VSI or for a free test license contact us.