Category: Citrix

Citrix Workspace Environment Management – IO Management

I’ve been blogging a lot this year on the merits of Citrix Workspace Environment Management (WEM) and the various features it provides. Another feature is I/O Priority – which enables us to manage the priority of I/O operations for a specified process:

To demonstrate this, I am going to run IOMeter (a storage testing tool – that consumes, but also measures CPU utilisation during testing), and SuperPi (a tool that calculates Pi to a specified number of digits – and consumes large amounts of CPU during calculation).

Before making any WEM configuration changes, on my virtual desktop the results are as follows:

IOMeter (Using the Atlantis Template – available here) –  shows 6.56% CPU Utilisation, and 3581 I/Os per second:

SuperPI calculation to 512K – 7.1 seconds:

Next I added the IOMeter and SuperPi executables into WEM, and set the priority to very low:

As a result of doing this the IOMeter results are significantly reduced, and the calculation time for SuperPi has increased significantly:

IOMeter Result – around 60% reduction in I/O per second, and 2% CPU usage reduction:

SuperPI – time to calculate has increased by nearly 200%:

From this test – it is clear to see that I/O Management within Workspace Environment Management is an effective way to control the I/O operations of specified processes. Whilst you might think slowing down the performance of an application is unlikely to be a major requirement for many of us – the ability to control particularly resource intensive applications is a definite win for complex environments. If a particular application is causing performance problems (for example degrading the performance for others) then this provides a suitable solution to manage that process.

Citrix Workspace Environment Management – Process Management

After testing out the excellent CPU and Memory management features in Citrix Workspace Environment Management (WEM), I wanted to blog about how processes can be controlled using the software.

Prior to starting this test, I have a basic Citrix XenDesktop environment configured, a WEM environment configured, and the relevant group policies in place to support this.

To prevent processes from running, we browse to System Optimization, and then Process Management:

From here we can enable process management:

Next – we have two options, we can whitelist, or blacklist. If we whitelist – only those executables listed will be allowed to run, whereas a blacklist will block only those listed.

I’m going to test out a blacklist:

We can exclude local administrators, and also choose to exclude specified groups – for example perhaps a trusted subset of users or specific groups of users who need to run some of the applications we wish to block.

For this test I am going to add notepad.exe to the list:

Next I saved the WEM configuration, refreshed the cache, and then logged into a Desktop Session to test the blacklist. Upon firing up notepad I am greeted with the message:

Bingo – a simple and effective way to block processes from running. This would be very effective when combined with a list of known malicious executables for example, or known problematic software items.

In a future release I’d love to see more granularity in this feature – for example blacklists, with the ability to whitelist processes for certain groups, rather than as a whole. This would enable control of applications on a much more granular level – for example, blocking “process.exe” for Domain Users, but allowing it for a trusted group of users.

 

Citrix Connection Quality Indicator

Overview

Connection Quality Indicator is a new tool from Citrix designed to inform and alert the user to network conditions that may affect the quality of the Session they are using.  Information is provided to the end user via a notification window which can be controlled using Group Policy.

Installation is supported on the following platforms:

See https://support.citrix.com/article/CTX220774 for more details.

Test Environment

My environment consists of a basic Citrix XenDesktop 7.12 installation:

  • 1x Desktop Delivery Controller (Local Database)
  • 1x Citrix StoreFront
  • 2x XenDesktop Session Host (Static VMs)

All VMs are 1 vCPU, 4GB RAM, and Windows Server 2016.

Installation

Connection quality indicator needs to be installed on each Session Host, or to a master template – and follows a simple next next finish installation with no configuration during install:

Post installation we can see the program installed via Control Panel:

Group Policy Configuration

As outlined in CTX220774 there are also Group Policy Templates that can be used. I have opted to copy these to the Central Store within my Domain. The templates can be extracted from any machine with Connection Quality Indicator on:

En-US templates are within the configuration folder ready for use:

Note – once placed into the Central Store, Group Policy Administrative Templates will be available as below:

Within Citrix Components we now have access to the Policy Settings for Connection Quality Indicator:

We are then able to modify the following settings:

Enable CQI – this setting allows us to enable the Utility, and also configure the refresh rate for data collection counters:

Notification Display Settings – from this setting we can configure the initial delay before the tool alerts the user to the connection quality rating, and define a minimum interval between notifications:

Connection Threshold Settings – this setting is perhaps the most interesting, because it is here we can tailor the tool to any specific environmental requirements. From this setting, we can control the definitions of High and Low Latency (in milliseconds), High and Low ICA RTT (in milliseconds), and the High and Low bandwidth value (in Mbps):

For the purposes of this demonstration – I’ve used default settings all round.

After configuring the group policies – I logged into a Desktop Session with the tool installed. 60 seconds after login the Window appeared with the session quality result:

If the cog symbol is clicked the user has the option to modify the location of the display window, snooze the tool, and also to see the test results:

Unfortunately, I have no method in my lab for degrading network performance artificially, or increasing latency etc. – but to prove that the metrics were functional, I adjusted the Group Policy settings so that some fairly unobtainable figures were used for all settings – and thus the tool would grade the connection quality differently:

This highlights how the tool can be used to identify connection quality through tailoring the GPO for a specific environment. After changing these settings, rebooting the Session Host (the lazy way of updating Group Policy!), and logging back in, the tool reported the following:

This is a very useful option within the tool – as we can specifically modify the settings to suit a range of environments. In some environments having low bandwidth might not be an issue, but high latency might be for example.

Conclusion

Overall this tool is very useful for giving the end user an insight into the quality of the network environment, and provides real time feedback on this quality. This is great for keeping end users informed, and managing expectations of performance too. What I also like is that end users will be able to see differences based on where they work – for example, a user with a “Strong Connection” inside the office, but a “Weak Connection” over 3G or at home, would know what sort of experience to expect, and would have real time data to support any troubleshooting moving forward.