As the title states, I would like to know the device count limit for OPC UA module for a single gateway. I estimate that a project will contain about 2000 bacnet devices.
According to my understanding, I need to create about 80 local_device and 2000 remote_device (that is, those in Device Connections).
This gateway is also responsible for 60,000 tags and 10 perspective sessions, which is a light load. The server hardware may be 32-core CPU and 128G memory.
So, do I need more gateways? Need higher hardware?
server sizing recommendations can be found in the above document. There's no software limit on number of devices, it's just based on what your server can physically handle.
Thanks, but there is no suitable reference in the documentation. I'm wondering if there are clearer guidelines, e.g. 4 cores and 8G memory for per 100 devices?
In addition, the device connection page does not seem to have a paging function. If 2,000 devices are really created, this page will be unusable. 
When I've chatted with sales before there's no such clear guideline as it depends greatly on how often you read tags from these and how you configure them all.
If your bacnet devices send data not very often they will require much less power than a device being read a few times per seond for example.
If you have 2000 devices being read quite often you may need to consider a scale-out architecture for your system.
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I see, thank you. The communication frequency of 90% of tags is once a minute. I would try this current configuration first.