All PMM MongoDB monitoring services are not working!

Hi team!
My mongodb sharded cluster has a total of 11 nodes, and both shards are P-S-S architectures. There are a total of 9 machines, deployed in two computer rooms, 6 machines in machine room A use the centos system, and 3 machines in machine room B use the ubuntu system.
pmm server version: 2.27.0
pmm client version: 2.27.0
When I added the 8th machines, the number of MongoDB services displayed by the pmm console suddenly decreased to 1, and the displayed monitoring data were all wrong.

I tried to rebuild the pmm service several times, but the addition failed when the total number of exporters was around 18. Is there a limit to the maximum number of monitoring services that pmm2 supports?It looks like the resources on the server side are not exhausted.

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hey @webstock_zt thanks a lot for your question, we don’t have any maximum number limit in terms of mongodb services you can add for monitoring, as long as you have enough resources,

This is from one of our test servers, could you possibly check for logs and exporter status and share some more information, probably it could be some other issue.

Could you also check the value for count(mongodb_up) using the explore the functionality and share it.

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Here is the count(mongodb_up):

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Here is my server logs.It was a .zip file.I changed the extension name.
pmm-server_2022-04-28_06-43.zip.log (96.7 KB)

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And this time I added 7 mongodb services at about 11:00 am. They worked well before 13:10.

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Hi @Punnet. Is it possible that the problem is caused by monitoring both Ubuntu and Centos systems?

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@webstock_zt No, I don’t think that should be a problem, I was looking at the logs and identified many errors related to failing agent connection, probably seems something related to that, I will log a bug about this and request a developer on the team to help investigate

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Hi@Punnet, After testing the deployment, we have found that the problem occurs in the network bandwidth bottleneck. thanks for your help!

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