A better application layering solution with UniDesk

UniDesk is now part of Citrix!

Are you wondering why?

I could try to bury you with a list of features, but I want to focus on one fundamental difference that I think explains why.

Let’s first look at the promise of application layering.

Traditionally, administrators would install an application into an image.  The same application might be installed across multiple images for different departments.  When the application requires an update, the administrator is forced to update the application multiple times, once for each image that contains the application.

Application layering tries to simplify this approach by creating a layer for each application.  Multiple applications layers are attached to a virtual machine, resulting in a complete desktop for the user.

I said “Application layering tries“, because there is a major limitation with many application layering technologies.

Most application layering solutions simply attaches each application layer’s virtual disk to the operating system image disk at startup or at logon.  Those virtual disks are seamlessly integrated so the user only sees a single drive within Windows Explorer.  However, as the number of attached virtual disks increases, the system performance decreases. This performance degradation results in a slow performing desktop and a bad user experience.

To combat this well-known issue, many application layering solutions recommend that the number of layers assigned to a single VM should be limited to 8-10 layers.  In order to achieve this, while still providing the users with the correct applications, we have to create application layers with multiple applications.


Do you see the problem with this recommendation?

The promise of application layering is that application management is simplified because each application is deployed within a single layer, meaning we only have to manage an application once.  But because of the limitations with application layering technologies, we have to create layers with multiple applications, resulting in a single application being part of multiple layers. This means we now have to managing the same application multiple times.

How is this  approach any better than managing our images like we did traditionally, with the operating system and applications installed natively?

This is one area with UniDesk is unique.

With UniDesk, each application layer contains one application, but UniDesk does not incur a performance hit like other application layering solutions.  UniDesk overcomes the application layering performance hit by merging all assigned layers into a single, complete image that gets deployed to users.

This might sound minor, but it is huge.  Instead of deploying a blank OS image and attaching application layers at startup or at logon, UniDesk creates an image where the OS and application layers are already merged. When you look at the details of the VM, you only see a single virtual disk.

This “small” difference overcomes the performance hit experienced by other layering technologies.

You might be asking if unidesk allows layers to be added elastically at logon. Yes it can.  But you wouldn’t do it for every app. Why would you?  There is a time and a place for both options (more on that in future blogs).

Visio Stencils for XenApp and XenDesktop 7.12

A short blog, but a good one.

New Citrix XenApp and XenDesktop Visio stencils, just in time for the 7.12 release.

visio712Items to note:

  1. Workspace Environment Manager: New component means new Visio stencil
  2. Federated Authentication Service: This feature was released in 7.11, but I didn’t have an image for it. Omission corrected
  3. Active Directory: Image is a replacement for an older image
  4. Machine Catalog: I needed an image for a diagram and realized it didn’t exist!

And because some of you continue to ask nicely, I created a set of Visio stencils in the Visio 2003-2010 format.

Daniel (Follow on Twitter @djfeller)
XenApp Advanced Concept Guide
XenApp Best Practices
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Citrix VDI Handbook 7.6

The Citrix VDI Handbook is now available!

Let me answer a few questions about the VDI Handbook

  1. Version: The VDI Handbook is based on the XenApp and XenDesktop 7.6 Long-Term Service Release.
  2. Updates: The plan is to release a VDI Handbook for each Long-Term Service Release. The VDI Handbook is based on real-world implementation experiences. Basing updates on LTSR releases (18-24+ months) allows us to include better recommendations than if we updated for the current release (every quarter).
  3. Format: PDF and HTML. The PDF version is ready now, the HTML version will be ready shortly.
  4. Content: The handbook includes information on Assess, Design and Monitor.

Grab version 1 of the Citrix VDI Best Practices Handbook for XenApp and XenDesktop 7.6

Daniel (Follow on Twitter @djfeller)
XenApp Advanced Concept Guide
XenApp Best Practices
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Full Clone VMs with Machine Creation Services

Since its inception, a Machine Creation Services VM was based on thin cloning technology.  Each VM would read from the same copy of the master image while any writes would be directed to a VM-specific differencing disk. Because the differencing disk only contains writes, it is often thin provisioned to save on storage space.

thin-cloneThis approach is perfect for pooled, non-persistent desktops.  But what about personal, persistent desktops?  With the XenApp and XenDesktop 7.11 release, Machine Creation Services now supports full cloned VMs.

full-cloneInstead of each VM reading from the same copy of the master image, each VM receives a full clone of the master VM’s disk. All reads come from the VM’s cloned disk and all writes go to the same disk.

If you recall, I spent some time discussing the differences between Machine Creation Services and Provisioning Services in order to help administrators better determine when to use which image management solution.  In fact, this discussion was spread across 7 different blogs

With this new capability, I need to make one addition to the summary.  Machine Creation Services now supports full cloned VMs.


Daniel (Follow on Twitter @djfeller)
XenApp Advanced Concept Guide
XenApp Best Practices
XenApp Videos

Citrix VDI Handbook

At Citrix Summit in January 2016, I heard from many of you asking for an updated version of the Citrix VDI Handbook.

At Citrix Synergy in May 2016, I heard from many of you asking for an updated version of the Citrix VDI Handbook.

At BriForum in July 2016, I heard from many of you asking for an updated version of the Citrix VDI Handbook.

To me, it sounds like you want the Citrix VDI Handbook to be updated.

The good news.  It is being updated!!!

The better news. We got our Citrix consulting experts to validate the recommendations

The bad news. It isn’t ready yet.

So why am I telling you this?

First, you can stop hounding me about getting it updated.  It is happening.  I am currently buried in Microsoft Word.

Second, I need to know if there are things missing that you think should be included.

And third, does this news make you happy?


XenApp Best Practice #5: Maintenance

It’s January. It’s midnight. It’s cold (-10F).

My telescope isn’t bringing this galaxy into focus.

My user experience is dreadful.

As I investigate, I shine a light at the front telescope and quickly see how years of dust and grit are causing my focusing issues.

IMG_5199(Click the image to see close up)

My lack of proper maintenance activities on the telescope just ruined a potentially wonderful night of observing.

When I first set up the telescope, objects were crystal clear. However, each subsequent time I rolled out the telescope, the quality degraded. The degradation was so minimal that it was not noticeable until one night things got so bad that I thought my telescope was junk.

I see the same thing happening in production XenApp/XenDesktop environments.

For example, when a new user is added, a new image is created or a new application is deployed, the experience is good. But slowly, over the course of months, the user’s logon time increases. It increases at such an incrementally slow pace, that the user doesn’t realize until their 25 second logon is now 50 seconds. The increase in time could be a result of a slowly growing profile, or new group policy preferences, or an ever-expanding logon script that supports new users and use cases.

Most of us focus on deployment and pay little attention to what happens next. That lack of focus will slowly erode the user experience. This is why maintenance is one of our core XenApp best practices.

XenApp Best Practice #5: Continuously delivering  the best user experience requires proper ongoing maintenance

Daniel (Follow on Twitter @djfeller)
XenApp Advanced Concept Guide
XenApp Best Practices
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PVS vs MCS – Part 7: Summary

As Q said in the final episode of Star Trek: The Next Generation, “All good things must come to an end” and after 6 previous blogs focusing on deciding between Provisioning Services and Machine Creation Services, it is time to end.

As I explained, over the past 5 years, improvements were made to Provisioning Services and Machine Creation Services.  While Provisioning Services simplified deployment and maintenance, Machine Creation Services improved performance and delivery capabilities.

Five years ago, if someone had to decide between the two, most likely the answer would be Provisioning Services.  But now in 2016, because of the overall improvements in both solutions, the decision will mostly focus on a few core concepts explained in the previous blogs:

Five years ago, I created a decision tree helping you select the most appropriate solution.  Developing these previous six blogs helped me do the same thing based on the latest advancements.

CompareDid I miss any criteria?  Let me know

Daniel (Follow on Twitter @djfeller)
XenApp Advanced Concept Guide
XenApp Best Practices
XenApp Videos



My virtual desktop journey