At the time I was working for a global pharmaceutical company, I was often confronted with the question how to set up a farm or design Zone for an environment around the world and ensure at the same time that users always have the best performance. Since I work for Citrix, I know that this issue is still very present. Every time I was visiting a client with a comprehensive approach XenApp or XenDesktop Farm site, the same question about the best design or Farm Zone has come at some point.
It is well known that the performance of XenApp and XenDesktop solutions is always relative to the performance of a desktop PC. In fact, users do not pay attention to the technical details of the solution or the source of the solution. Therefore, a fast and stable environment must be provided to users within the LAN and WAN.
In this blog, I will describe the different needs of the end user regarding the ease of use of a XenDesktop Hosted VDI Desktop, XenApp Hosted Shared Desktop or published applications in a global environment and its implications for XenDesktop and XenApp Farm website design. To see how a XenApp farm design should look like from the perspective of an administrator and get more information about zone concepts, I recommend you read Nicks great blog on this topic.
But before you start with the main topic, I have to do the usual coverage Board ;-). First of all the recommended design and configuration of proposals must be verified in a dedicated test environment before implementing them in the production environment. Not all solutions and parameters have the same result, each environment is somewhat unique. The solutions provided and parameters can have different behaviors. However, the good news is: all proposed solutions are fully supported by Citrix
End User Requirements
Unfortunately, the needs of end users are often under -estimés and not collected at all .. in the end, however, your personal goal is to fully meet the needs of end users. Therefore, all the needs of users from all regions / sites should be collected before starting with XenApp or XenDesktop design. In most cases, the requirements of the LAN users are not the same influence on the design than those of WAN users. Users accessing the environment within the local network have enough overall bandwidth, closer to zero latency and stable network infrastructure. So let's focus on the WAN users.
Before deciding on the need for a dedicated farm or site for the region or a particular site, you must know how users work and what kind of applications or desktops that they use . There is a huge difference between using a desktop application or a desktop with a multi-media content. First, you must be aware of the type of applications that are used. In addition, it is important to know the processes and applications of their behavior. In short, the creation of an end-user "usage profile" is essential. Especially for WAN users, it is important to know how applications behave in the event of a delay occurred in a user action. After some key questions I suggest asking your users to find out what is expected type of use:
- Are they use applications or desktops
- East -what application or desktop to have a multi-media content?
- Internet Explorer is used?
- how intensely and how are they time using applications or desktops?
- What is the bandwidth and latency of the available user site?
It is generally known that applications with high graphics requirements (Internet Explorer, Windows Media Player, graphics editing program) do also have network requirements and high material. The contents of these applications must be updated frequently and therefore more screen updates occur. More screen updates lead to greater use of network traffic
Implications for Farm / Design
So the question is now :. What are the conclusions of user feedback and what are the implications for your farm or site design? Let's start with an extreme example and make a transition to floating consequences. Once I saw an environment where users had 320 ms of latency and used a XenApp application with local text echo enabled (Switzerland - Australia). It was a Service Desk application with very low graphics requirements. Users were able to work normally. At the same time, I must say that this configuration according to the circumstances mentioned above would not be suitable for all applications and the environment. With such high latency applications with a large amount of content updates do not work properly. Also, if you have users working quickly or over a longer period (more than 6 hours per day), high latency prevent effective work. I propose my clients to build a dedicated farm or site given the following circumstances:
- greater than 150 ms latency and the desktop application or intensive use (6 hours or more)
- Latency above 150 ms and high graphics applications (including multimedia content and Internet Explorer)
- Latency greater than 150 ms and the use of a XenDesktop or XenApp office as the primary platform
- latency above 300 ms
I have defined as 150 ms latency limit described above recommendations. The 150 ms have no technical background, but from my own experiences and made my logical point of view in combination with the described scenarios.
For all other scenarios, I would choose a centralized farm or site configured with the following optimization settings listed.
Optimizations
XenApp and XenDesktop provides the performance enhancements of the box to the HDX components. Like many administrators are not using them, I will focus only on these parameters to show the impact on network traffic. Optimizations applies to XenApp 6.5 and XenDesktop 5.5 / 5.6.
In most XenApp and XenDesktop environments I reviewed, there was only one policy set for all users. But the "one solution" does not work in a global environment, so I usually insists create at least two additional user policies in addition to the basic policy. One for LAN and one for users WAN. and of course, you can create a separate policy for each site with specific parameters.
for LAN users, there is normally no need for optimization of ICA traffic. the WAN communication optimization is ensured by our large HDX Adaptive Orchestration feature, which assesses client resources for the end user, the bandwidth and server resources to determine the best delivery method for high-definition user experience. While stating our own settings to maximize performance, HDX Adaptive Display functions will be limited automatically. please be aware that the optimizations described below are based on performance improvements where network traffic, but also the quality display will be decreased not as HDX Adaptive Orchestration, where high-definition user experience is always provided .
Max fps parameter indicates the maximum number of frames per second sent to the customer. The default value for XenApp 6.5 and XenDesktop 5.6 is 24 fps and is configurable up to 30 fps. To increase performance and reduce bandwidth, set the fps of between 10-15 fps
Minimum Image Quality :. Sets the minimum acceptable image quality. Minimum quality image is linked to the Lossy compression level, which defines the starting image quality. Adaptive Display then adjust the JPEG quality between the level of compression with loss and minimum image quality. Configure minimum image quality at (quality min image = 15) Low
extra color compression :. When enabled, Extra Color Compression uses the lower resolution color images where bandwidth is less than the threshold. Therefore, the adjustment depends on the additional threshold Color Compression. Set the threshold to the maximum value, which is 4,294,967 Kbps, to ensure that all connections with a bandwidth less than the set value using Extra Color Compression
Compression Heavyweight :. Heavyweight compression allows you to further reduce bandwidth without loss of image quality by using a more advanced, but more CPU-intensive, graphical algorithm. If enabled, Heavyweight compression applies to all lossy compression settings
Lossy compression level :. Lossy compression eliminates redundant or unnecessary information in the data stream. higher compression results in a greater loss of image quality and thus in too much bandwidth and savings packages. The higher compression used, less fps. Configure the level of high Lossy compression (from image quality = 25) and define the associated maximum threshold (2,147,483,647 Kbps).
optimization results
But optimization really help? To prove the savings and network traffic performance I created a workflow with EdgeSight Active Application Monitoring to ensure that all tests have the same procedure. During the workflow of recording (11 min.) I used Adobe Reader for PDF files, written documents with Microsoft Office Word, use Windows Explorer to browse folders, view photos and use Internet Explorer to browse on the Web. We can say that this procedure represents a typical worker-task. In addition, I used a WAN emulator to reproduce the different latency values. The bandwidth has been reduced because I focused only on the latency optimizations. For a true basis I performed this procedure 15 times with the default policy settings and captured the amount of network packets and bytes transferred average bandwidth for the duration of the session. Then I ran the same workflow with optimizations mentioned above. The results are summarized in the following table:
As you can see, there is a reduction of network traffic in all measures. During the basic strokes (default settings) I registered a number of packets between 12 255 and 23 376, megabytes transferred ranged between 7.6 and 14.1 and the bandwidth used between 0 Kbps and 164 Kbps. The results of the optimized parameters were better and had a smaller gap. The number of packets in total ranged from 9376-10363, transferred Mbytes of 6.5 to 7.3 to a bandwidth of 76 Kbps to 84 Kbps. Before completing the analysis of network traffic, I must emphasize, that the greatest savings results from reducing fps. Therefore, without any application with a high rate of updates to the screen, I recommend you reduce the fps before changing the compression settings or lowering the display quality. The measured results are valid for the scenario described above. They may vary depending on the environment used.
As you have recognized, we focus on flash and multimedia optimization, as there is already a very detailed white paper available on this subject. I highly recommend studying "best practices and recommendations for 3 Citrix Receiver with XenDesktop and HDX technology" paper, where all the functions of HDX and out of the box flash and multi-media optimizations are very well described.
Because there is no one way to do so, please share your experiences with optimizations. What parameters generated increasing your most valuable performance?
I hope you have enjoyed reading all comments are welcome; -.)
Best regards
Saša Petrović
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