Containers Expo Blog Authors: Liz McMillan, Yeshim Deniz, Elizabeth White, Zakia Bouachraoui, Pat Romanski

Related Topics: Containers Expo Blog

Containers Expo Blog: Article

Improper Resource Allocation

Top 10 mistakes to avoid with virtual desktops

If you ask me what type of desktop I need, I'm going to give you specs for the most powerful, uber-cool desktop on the market.  But if you look to see what desktop resources I need, you will see that the specs are quite a bit lower: 1 core and maybe 2 GB of RAM. In fact, when I look at my resource consumption, I get close to 2 GB of RAM by the end of the day due to the number of applications I have running, memory leaks in some of my applications, and applications not freeing up memory when closed.

Like me, many users only consume a fraction of their total potential desktop computing power, which makes desktop virtualization extremely attractive. By sharing the resources between all users, the overall amount of required resources is reduced. However, there is a fine line between maximizing the number of users a single server can support and providing the user with a good virtual desktop computing experience.

Improperly allocating resources to the virtual desktops is the 7th most common mistake make. Other mistakes, discussed previously, include:

10.  Not calculating user bandwidth requirements

9.    Not considering the user profile

8.   Lack of Application Virtualization Strategy

One of the lessons we learned from virtual desktop implementations is trying to push the hypervisor, any hypervisor, too hard results in a poor user experience. The following recommendations help optimizing the environment by focusing on the hypervisor:

Parameter Hypervisor Description
CPU Allocation Citrix XenServer
Microsoft Hyper-V

VMware vSphere

Users should start with a single vCPU and be granted a second if needed due to the following:
  • Most user-based applications are only single-threaded and will not benefit from a multiple CPU configuration.
  • Many user applications do not require significant amounts of processing, which negates the need for more CPU power.
  • By allocating multiple vCPUs for each virtual desktop, extra resources are required to switch requests across the different cores.
Command Tuning Citrix XenServer
Microsoft Hyper-V

VMware vSphere

The XenDesktop controller sends low-level commands to the hypervisor layer to perform tasks on the virtual machines (start, stop, reboot, etc). If too many tasks are sent out simultaneously, the connection to the hypervisor layer can become sporadic. These tasks often have a large impact on the server resources, which impacts the users. It is advisable to throttle the number of commands sent.
Transparent Page Sharing VMware vSphere Transparent Page Sharing allows the vSphere hypervisor to share portions of memory that are identical between virtual machines. This has the potential to improve the virtual desktop performance by having a positive impact on memory consumption.

This feature will typically only provide value in older operating systems, like Windows XP and Windows Server 2003, which have 4KB memory pages.  Newer operation systems, like Windows 7 and Windows Server 2008, have large memory pages (2MB) by default. The larger memory pages makes the likelihood of finding exact duplicates of memory very difficult. .

Memory Ballooning

Memory Overcommit

VMware vSphere

Note: XenServer and Hyper-V support for dynamic memory is new. It is assumed the results will be similar, but testing is required.

Memory ballooning or memory overcommit shifts RAM dynamically from idle virtual machines to active workloads. Memory ballooning artificially induces memory pressure within idle virtual machines, forcing them give back memory so other virtual machines can consume it (each hypervisor does it differently but the overall concepts are similar).
In practical applications, this has shown to be an impediment to positive user experiences. Forcing virtual desktops to free up memory is only a temporary solution. If a large group of idle or low-usage virtual desktops become active (after lunch, for example), they will require more memory. But if many of the virtual desktops on the same hypervisor are experiencing increased loads, where will the extra memory come from? With no free memory, the hypervisor is forced to page to disk, which is slow.

A desktop is not a server. A desktop is running desktop applications which often have more memory leaks and poor cleanup processes when compared to server applications. Most desktops consume more memory as the day progresses due to these leaks, which will put strain on any overcommit feature. It is advisable to disable this feature.

What other suggestions do you have for optimizing the hypervisor in a desktop virtualization world?

Daniel - Lead Architect

More Stories By Daniel Feller

Daniel Feller, Lead Architect of Worldwide Consulting Solutions for Citrix, is responsible for providing enterprise-level architectures and recommendations for those interested in desktop virtualization and VDI. He is charged with helping organizations architect the next-generation desktop, including all flavors of desktop virtualization (hosted shared desktops, hosted VM-based desktops, hosted Blade PC desktops, local streamed desktops, and local VM-based desktops). Many of the desktop virtualization architecture decisions also focuses on client hypervisors, and application virtualization.

In his role, Daniel has provided insights and recommendations to many of the world’s largest organizations across the world.

In addition to private, customer-related work, Daniel’s public initiatives includes the creation of best practices, design recommendations, reference architectures and training initiatives focused on the core desktop virtualization concepts. Being the person behind the scenes, you can reach/follow Daniel via Twitter and on the Virtualize My Desktop site.

IoT & Smart Cities Stories
Moroccanoil®, the global leader in oil-infused beauty, is thrilled to announce the NEW Moroccanoil Color Depositing Masks, a collection of dual-benefit hair masks that deposit pure pigments while providing the treatment benefits of a deep conditioning mask. The collection consists of seven curated shades for commitment-free, beautifully-colored hair that looks and feels healthy.
The textured-hair category is inarguably the hottest in the haircare space today. This has been driven by the proliferation of founder brands started by curly and coily consumers and savvy consumers who increasingly want products specifically for their texture type. This trend is underscored by the latest insights from NaturallyCurly's 2018 TextureTrends report, released today. According to the 2018 TextureTrends Report, more than 80 percent of women with curly and coily hair say they purcha...
The textured-hair category is inarguably the hottest in the haircare space today. This has been driven by the proliferation of founder brands started by curly and coily consumers and savvy consumers who increasingly want products specifically for their texture type. This trend is underscored by the latest insights from NaturallyCurly's 2018 TextureTrends report, released today. According to the 2018 TextureTrends Report, more than 80 percent of women with curly and coily hair say they purcha...
We all love the many benefits of natural plant oils, used as a deap treatment before shampooing, at home or at the beach, but is there an all-in-one solution for everyday intensive nutrition and modern styling?I am passionate about the benefits of natural extracts with tried-and-tested results, which I have used to develop my own brand (lemon for its acid ph, wheat germ for its fortifying action…). I wanted a product which combined caring and styling effects, and which could be used after shampo...
The platform combines the strengths of Singtel's extensive, intelligent network capabilities with Microsoft's cloud expertise to create a unique solution that sets new standards for IoT applications," said Mr Diomedes Kastanis, Head of IoT at Singtel. "Our solution provides speed, transparency and flexibility, paving the way for a more pervasive use of IoT to accelerate enterprises' digitalisation efforts. AI-powered intelligent connectivity over Microsoft Azure will be the fastest connected pat...
There are many examples of disruption in consumer space – Uber disrupting the cab industry, Airbnb disrupting the hospitality industry and so on; but have you wondered who is disrupting support and operations? AISERA helps make businesses and customers successful by offering consumer-like user experience for support and operations. We have built the world’s first AI-driven IT / HR / Cloud / Customer Support and Operations solution.
Codete accelerates their clients growth through technological expertise and experience. Codite team works with organizations to meet the challenges that digitalization presents. Their clients include digital start-ups as well as established enterprises in the IT industry. To stay competitive in a highly innovative IT industry, strong R&D departments and bold spin-off initiatives is a must. Codete Data Science and Software Architects teams help corporate clients to stay up to date with the mod...
At CloudEXPO Silicon Valley, June 24-26, 2019, Digital Transformation (DX) is a major focus with expanded DevOpsSUMMIT and FinTechEXPO programs within the DXWorldEXPO agenda. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throug...
Druva is the global leader in Cloud Data Protection and Management, delivering the industry's first data management-as-a-service solution that aggregates data from endpoints, servers and cloud applications and leverages the public cloud to offer a single pane of glass to enable data protection, governance and intelligence-dramatically increasing the availability and visibility of business critical information, while reducing the risk, cost and complexity of managing and protecting it. Druva's...
BMC has unmatched experience in IT management, supporting 92 of the Forbes Global 100, and earning recognition as an ITSM Gartner Magic Quadrant Leader for five years running. Our solutions offer speed, agility, and efficiency to tackle business challenges in the areas of service management, automation, operations, and the mainframe.