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Chethan Rp avatar image
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Chethan Rp asked Ben Wilson commented

FlexSim webserver takes more time to create instances

FlexSim webserver has been taking a lot of time to create instances and then again takes more time to load the model of the created instance. Also, we are facing issues when it comes to terminating old instances. When we try to terminate old instances, it fails to terminate them too.

FlexSim 22.1.2
webserverflexsim webserverflexsim web server
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Ben Wilson avatar image Ben Wilson ♦♦ commented ·

@Chethan Rp ,

What does your RAM and CPU utilization look like on your server? Do you have many unterminated instances that are using resources? Have you tried rebooting your webserver? Does the webserver immediately exhibit this behavior after a fresh reboot, or does it happen over time as instances remain running and consuming more and more resources?

In your statement "when we try to terminate old instances, it fails to terminate them" I assume you mean through the default web interface? Or have you logged into the webserver and attempted to kill the instances manually (probably using Windows Task Manager)?

Does your model exhibit any kind of exceptions or other errors when you run different scenarios (unless you are sending exception data through a custom web interface, you would need to test this using FlexSim's native Windows interface rather than over the webserver)? If so, these should be resolved to make sure they are not the root of the issue.

Any further information you can provide may help us in giving you better advice. Or if you can provide a copy of your model and steps to reproduce we could help to debug.

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Chethan Rp avatar image Chethan Rp Ben Wilson ♦♦ commented ·

Hey @Ben Wilson,


This has been a recent issue that I have seen with the FlexSim webservers. Even if there are some unterminated resources or not, it is taking a lot of time to create a new instance. I have been referring to the default FlexSim webserver here. Apart from this, we have an option called "Terminate All" which terminates all instances on the default FlexSim webserver. But, I have been facing issues with terminating these old instances as well, unless I terminate those instances manually from Task Manager of the server. Loading a basic model through the FlexSim web server after creating an instance is also taking more time. Please do let us know if we should make any specific changes in the webserver configurations or guide us with any process that speeds up the model loading time.





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Ben Wilson avatar image Ben Wilson ♦♦ commented ·

@Chethan Rp

You mentioned "this has been a recent issue that I have seen with the FlexSim webservers" which implies that you used to have a better experience, but that performance now is degraded in comparison.

If so:

  1. Was this change concurrent with some other change, such as:
    1. upgrading to a new FlexSim version
    2. upgrading to a different webserver version
    3. upgrades to Windows
    4. hardware change or new hardware altogether
    5. or anything else that may have changed from when the webserver worked better?
  2. Did you recently change the graphics streaming settings in your models from video (the original method for sending the 3d views) to WebGL (a new option introduced in version 20.2)? See video streaming and webgl streaming bullet points here: Webserver (flexsim.com)
  3. Have you watched the Task Manager on the server while it is in use? It would be interesting to know how resource utilization changes, from a cold restart of the server, to starting the first FlexSim instance, to the 2nd, to the 3rd, then shutting instances down to see if resources are able to be reclaimed, and how resource utilization changed with each added instance.

Based on your description that the issue even manifests with a basic model right after a reboot, the following ideas are less likely, but still worth looking into:

  1. Do you have more users hitting the web server now than before?
  2. Are you running more concurrent instances now than previously?
  3. Do you have adequate hardware on the webserver for each concurrent FlexSim instance that may be running? Remember, you need enough hardware resources on your PC for each FlexSim instance to get all the RAM it may need throughout the course of its simulation run, along with CPU and good disk access, plus a good percent of hardware allocated for general overhead like Windows and other apps and unrelated background processes.
  4. Are your models bigger now than they used to be when your webserver worked properly?

You mentioned "Loading a basic model through the FlexSim web server after creating an instance is also taking more time." Do you mean that starting the instance takes the same amount of time, but connecting to it with the web browser is now taking longer than it used to?

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Chethan Rp avatar image Chethan Rp Ben Wilson ♦♦ commented ·

Hey @Ben Wilson ,

We didn't do any upgrade of FlexSim/webserver version. Also, we didn't make any graphic streaming settings. Ending the task from Task Manager does help in closing the instances that were created. However, this cannot be a long term solution though.
Apart from these, it always took more time to load/create instance of a model in flexsim webserver.

Even if we are trying to load models in our local, it does take more time. We do not have more users hitting this web server at the same time and we are not running more of concurrent instances at the same time. Also, we do have adequate hardware required to render this model and it has good ram. Anyways, size of the model does vary from one another but it should not affect drastically in terms of rendering where it takes few minutes to load/create the instance

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Ben Wilson avatar image Ben Wilson ♦♦ Chethan Rp commented ·

@Chethan Rp,

What are your webserver hardware specs and OS? Please include CPU, RAM, GPU, and OS version+build (use the winver command).

What versions of FlexSim and the Webserver are installed?

Are you accessing the webserver over a local area network, a VPN, the public Internet, or something else? What kind of proxies, firewalls, network appliances, etc, sit between the server and connecting clients?

Are there particular models you can share with us that exhibit this problem?

So far we haven't gathered enough info to suggest what the issue might be. We need to be able to duplicate the problem. Hopefully the above will help us do so.

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Jeanette F avatar image Jeanette F ♦♦ commented ·

Hi @Chethan Rp,

We haven't heard back from you. Were you able to solve your problem? If so, please add and accept an answer to let others know the solution. Or please respond to the previous comment so that we can continue to help you.

If we don't hear back in the next 3 business days, we'll assume you were able to solve your problem and we'll close this case in our tracker. You can always comment back at any time to reopen your question, or you can contact your local FlexSim distributor for phone or email help.

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Chethan Rp avatar image Chethan Rp Jeanette F ♦♦ commented ·
Hi @Jeanette F and @Ben Wilson,


It was helpful to delete the created instances. But, we are still not able to load model in an efficient way. It takes more time to load a model and create an instance. Any help to resolve this issue would be appreciated.

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Jeanette F avatar image Jeanette F ♦♦ Chethan Rp commented ·
If you answer the questions that Ben Wilson asked then we can help more.
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Jeanette F avatar image Jeanette F ♦♦ commented ·

Hi @Chethan Rp,

We haven't heard back from you. Were you able to solve your problem? If so, please add and accept an answer to let others know the solution. Or please respond to the previous comment so that we can continue to help you.

If we don't hear back in the next 3 business days, we'll assume you were able to solve your problem and we'll close this case in our tracker. You can always comment back at any time to reopen your question, or you can contact your local FlexSim distributor for phone or email help.

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