Thin client devices are simpler than computers, but they can still have performance issues. I looked at trying to find the nature of the performance issues and where to look for answers.
Thin Client Performance issues? Thin clients can experience a number of performance issues resulting in slowing down or even a complete disruption of the user experience. Leading to slow login times and poor desktop refreshes, where there is a lag between moving the mouse or pressing the keyboard and the resulting change appearing on the desktop.
Many of the issues will not be with the thin client itself but with the remote servers the thin client connects to. So it is vitally important to work out whether the performance issue is with the thin client or the remote server the thin client connects to, before trying to engage on a course of action to try to fix the performance issue.
Below I’ve listed the common issues experienced by thin client users and what could be causing these issues.
1. Slow logins
Some thin clients can integrate with authentication services like Microsoft Active Directory directly, allowing users to pre-authenticate themselves. Then these pre-authenticated credentials are automatically passed through to the virtual desktop session, avoiding the need to log in twice. Once for the thin client and then again for the virtual desktop session.
Slow logins at the thin client stage could indicate issues with the authentication service, requiring further investigation. It’s also worth while checking the network cables to make sure the these are not loose, and the thin client can make connections across the network.
Slow logins to the virtual desktop from the thin client could indicate network issues whereby the bandwidth available is constrained, may be through contention from many other devices using the same network connections such as Wi-Fi.
Or there could be issues with the remote servers the thin client connects to not having the resources to timely deal with the login requests.
Overloaded servers can cause logins to slow down. I’ve seen cases where because of bad weather, more people decided to work from home and the company didn’t have enough servers to cope with the additional demand.
This led to extremely long login times and in the end the company decided to prioritise who could and who couldn’t log on to company services. I was classed as not important enough to log in, so I got a paid day off instead.
2. Slow desktops
Once the login part has been successful, if the time taken for the virtual desktop to become fully functional takes a long time could be systematic of performance issues on the remote server or network issues and not the thin client itself.
Other symptoms could include the virtual desktop freezing and taking a few seconds to come back to life, with this repeated several times or just intermittently.
3. Slow screen refresh
Symptoms of slow screen refresh include mouse movements taking longer than expected, so moving your mouse left isn’t instantaneous, instead taking a few seconds to catch up. Likewise, key strokes aren’t immediately showing up on your desktop and sometimes you can type in several words and it takes several seconds for them to all appear.
If everyone else in your vicinity is not having the same issue, then this could be an issue with the hardware in your thin client.
If everyone else in your vicinity is experiencing the same issue of the desktop screen taking time to refresh
4. Connection Errors
Not being able to connect to the virtual desktop or virtual applications is another common problem. This is down to issues with the remote server not being able provide applications due to some fault or error.
These types of issues will be the responsibility of the administrators of the remote servers and won’t involve any troubleshooting on the thin client.
The remote servers depending on the flavour of remote software being used (Citrix XenApp XenDesktop, VMWare Horizon, Microsoft RDP) the thin client will normally disconnect from a session if the network connection fails or there isn’t enough bandwidth for the connection to kept alive.
This is better than resetting the connection and the user losing all their work as any unsaved changes will be lost.
5. Reconnections stall
When disconnections occur, some of the software used by the thin client to connect to the remote servers, Citrix Workspace (formerly Citrix receiver) for example, has the ability to try to reconnect to the session that has been disconnected.
This normally happens quite quickly but if it takes time for Citrix Workspace to reconnect to Citrix XenApp or Citrix XenDesktop sessions, then this could be an issue with the network.
6. Bad updates
Thin client devices can sometimes need updates to their firmware, so their operating systems can get the latest security patches as well as additional features and fixes. These should always be tested on individual thin clients first in isolation to see if they don’t introduce any issues.
I’ve done some testing myself and found some updates have caused issues and I’ve decided to postpone any updates until a further fix was made available by the vendor. By not testing the updates and plodding along by installing them, the thin clients would have created problems.
How do you troubleshoot a thin client?
Thin client issues can be isolated into the following five areas:
- Remote servers
Check the thin client hardware to make sure there’s no issues. With some thin clients they have diagnostics built in and these can be run when the thin client is started up.
Check the network connections including the network port on the thin client, the network cabling to the network points as well as checking to see if the overall network is functioning satisfactorily by checking other devices on the same network.
With Wi-Fi connections, check to see if the thin client is able to connect and get an IP address. Check to see if other devices on the Wi-Fi network work as expected.
For 4G and 5G connections, check to if the thin client is able to connect and obtain an IP address. Try other devices on the same 4G or 5G connection to see whether they work.
Thin client devices have operating systems like Windows IoT to Linux based custom thin client operating systems like ThinStation and OpenThinClient. Check to see if these are not exhibiting any errors by checking error events and error logs, if possible.
The actual software to make the thin client connect to the remote servers should also be checked. This software such as Citrix Workspace, Microsoft RDP client to VMWare Horizon client may need updates or may have had bad updates causing them to not work properly.
Check any integration like authentication from the thin client to Microsoft Active Directory is working correctly.
5. Remote Servers
If everything on the thin client, the network and integrations seem fine, the next place to check will be on the remote servers. Check to see if the remote servers are not overloaded or have too many disconnected sessions.
Check to see if the remote server networking and the integrations with an authentication service, for example, like Microsoft Active Directory are working as expected.
How do you measure thin client performance?
Firstly, you will need to know how a thin client system operates. You’ll need to know the two components in a thin client system, which are:
- the application itself which executes on a remote server and
- the thin client application which executes on the thin client.
The remote server runs the applications the user will use, while the thin client runs the thin client software that delivers the users input from mouse movements and key strokes to the server across the network and accepts the update screen images from the server to display on the user’s display.
The network can be checked by using networking monitoring tools to see how the data moves across the network, including the time taken and how much data ends up being lost (dropped) and requires retransmission.
As more retransmissions mean the data takes longer to get through and slows down the user experience.
With limited bandwidth connections, like those to branch networks or home connections, the remote display performance can be optimised using the following techniques:
With the above techniques, the performance of the thin client becomes more usable for the user. Any performance should be judged by how the user experiences their desktop connections and not just on metrics from monitoring tools.
The remote servers can also be monitored to see if they are coping or running out of resources. This will allow for bottlenecks to be quickly determined and effective remediation put in place.
It’s essential to know the different remote display protocols that the thin client supports as these protocols are responsible for transferring data from the remote servers to and from the thin clients. Any problems with these remote protocols can also affect overall performance.
There are three common display protocols, these are:
- Microsoft’s Remote Desktop Protocol (RDP)
Microsoft RDP is suitable for delivering fast local network on the desktops but doesn’t cope with less reliable and slower networks.
HDX has been developed by Citrix Systems and is suitable for handling high latency networks and low bandwidth.
PCOIP is used by VMWare Horizon clients to provide connections to VMWare Horizon servers from thin clients running the VMWare Horizon client.
Some thin clients are able to support multiple protocols making it easy to connect to different types of remote software used by the remote servers.
Thin clients can experience many performance issues, but these are generally not tied to the thin client hardware and are networking related or issues with the remote servers the thin clients connect to.
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