In our datacenter I'm having throughput issues if a server is connected on a 10G port on the switch. For debugging I already removed our router and asked our ISP for a small IP range that I can use directly. This way I can rule out a problem with the router.
So, right now the setup is very simple but the problem is still there.
ISP (1G link) -> Ubiquity ES-16-XG switch -> 10G Servers
Nothing more. Nothing less.
Now, when doing an iperf3 test from a remote location I'm only getting an average 200mbit in download (seen from the remote location) and 900mbit while uploading (seen from the remote location).
If I force any server from 10G to 1G on the switch, the throughput problem is gone. I get 900mbit in both directions.
This made me think that maybe the switch was the problem. The thing is: when I test locally, between a server on 1G and another server on 10G, iperf3 shows 940mbit in both directions. So the switch seems okay.
I hope someone knows what's happening here and what I can do about it.