Problem Definition:

Users report poor, slow, or sluggish virtual desktop performance.  Applications appear slow to load, typing/keystrokes may feel unresponsive, dragging application windows inside the desktop may also appear slow.  Users may become disconnected and get error messages upon being disconnected such as “Citrix HDX Engine has Stopped Responding."

Cause:


    This sort of performance complaint generally indicates an issue with the user’s internet connection or local workstation or resource starvation on the Citrix Desktop Host (low memory/CPU).Rarely does this indicate a congestion and/or latency issue with the CloudConnect infrastructure.This Article will assist in identifying the cause.


Resolution:


    Most performance issues are caused by virtual machine snapshots, inadequate CPU/Memory allocation to the virtual machine, the incorrect Citrix Receiver/Workspace version, or network congestion/packet loss with the customer's ISP.


    First, it is  best to check if there is a snapshot on the virtual machine in vCloud Director.  A snapshot slows down disk I/O in a virtual environment.  If there is a snapshot, remove the snapshot.  For additional information on snapshots, see: CloudConnect Docs: Managing Virtual Machine Snapshots   


    To add CPU/Memory resources to the Virtual Machine, see: CloudConnect Docs: Managing Virtual Machines: Edit Virtual Machine Hardware Configurations


    To measure/log network latency, Citrix provides the following tools: Citrix HDX Monitor (for realtime visibility into network conditions), or Citrix Connection Quality Indicator (to log intermittent issues).  Note that the Citrix Connection Quality Indicator must be obtained from the DesktopConfig installation media.


    As of the publishing of this article, the recommended Citrix software for customers accessing virtual desktops from Windows PCs is Citrix Receiver 4.9 LTSR CU9


   If Windows Operating System file corruption is suspected, the following commands may be run from an elevated command prompt:


        DISM /Online /Cleanup-Image /RestoreHealth

        sfc /scannow


     Note: If the above DISM fails with error 0x800f081f, see: CCT-202006121 - DISM fails with "The source files   cannot be found" error 0x8000f081f


   Third party Antimalware agents can cause severe performance problems on a Citrix Server.  It is recommended to not use third party antimalware agents, rather CloudConnect recommends the Default Windows Defender Security configuration in combination with Windows AppLocker.


     It is also recommended that you upgrade the Citrix Server software to the latest CloudConnect configuration. This will included fixes for known issues that could affect performance or system stability.  For more information, see: Upgrade a Citrix Server Configuration to the Latest CloudConnect Baseline


    

      The following steps can provide a basic level of triage of some of the above issues.

Step 1:

It is best to begin by ruling out issues with the user’s Internet Service Provider. From the user’s workstation open a command prompt and enter the following: 

 “ping –t 216.93.253.193”

 

If dropped packets occur and/or latency is frequently and/or consistently greater than 70ms, contact your ISP to troubleshoot.This may include resetting your modem.It could also indicate a problem with the on-site network, LAN or WLAN if applicable.

If the output above yields a reply “time” value consistently less than 70ms and there are no replies dropped (i.e. “request timed out”), then the ISP is not likely the cause, and proceed to the next step.

Step 2:

If the ISP is not the cause as determined in the previous step, proceed to check the resource utilization on the user’s local workstation.Open the task manager on the local workstation and verify the memory and/or CPU utilization are less than 70%.For example, the following image shows resource contention on the local workstation because the memory consumption is 2.82 GB / 3.72 GB available:

 

It is also possible for excessive CPU utilization to cause a problem.Use the processes tab to identify the culprit process and disable/remove unnecessary programs.It should be noted that the Citrix Receiver utilizes minimal processor and memory resources.

Step 3:

If the above step does not indicate an issue with local workstation resource contention, resource contention the Citrix Desktop Host. Using your “support” account, access the affected Citrix Desktop Host for the user group or user complaining of performance problems.

Open the Task Manager and/or Resource Monitor on the Citrix Desktop Host and (similar to Step 2 above) look for either Memory or CPU starvation.Generally Memory utilization above 85% and/or CPU utilization consistently above 70% will indicate a need for additional resource pool(s) to be provisioned to accommodate the user demand on the Citrix Desktop Host.If additional CPU and/or memory is required, open a Ticket with CloudConnect Technical Support to add an additional resource pool to the Citrix Desktop Host.

Additional Information:

If all of the above troubleshooting steps do not identify a cause, open a Ticket with CloudConnect Technical Support. Ask the Technical Support Engineer to investigate possible virtual machine snapshot growth pursuant to KB Article CCT-201410083.

      For Citrix environments where a Citrix bug is suspected (for example after upgrading the Citrix software to a new version), a CDF trace may be required to identify the root cause.  This root cause analysis process can take several weeks and should be used as a last resort when all other options have been exhausted and no workaround is available.  Contact CloudConnect Technical Support for additional information.


Applies To:

Microsoft Windows Desktop and Server Operating Systems XP/2003 and later

Citrix Apps & Desktops