I’ve been troubleshooting this issue for days now, but haven’t found a solution yet. So here it goes.
I’ve 3 Proxmox v9 hosts. All with different CPU types (Intel Xeon, Intel i9 and AMD Ryzen). Among other vm’s, there are 3 guests (Windows 11, OpnSense and OpenWRT) that are running OpenVPN inside them. I’ve created these 3 guests to see if the issue is OS related.
The issue is that once OpenVPN is active inside the vm, it’s internet throughput is only 250Mbps when the guest resides on 2 of the 3 hosts. As soon as I disconnect the VPN, throughput is back to its normal 700-800Mbps. When I migrate the guest to the host with the Intel i9 CPU, the VPN speed is almost the same as the speed without VPN, around 700Mbps.
I’ve checked all settings: MTU, disabled offloading in the guest, changed cpu type to ‘host’, tried different nic types, changed the host nic, but nothing helps. Only on the Intel i9 host, throughput is normal, on the others it’s only one 3rd.
Also changing the VPN type inside the guest doesn’t help.
All hosts are connected to the same network switch.
My guess is that it’s some sort of host configuration/issue, because migrating the vm to one specific host solves the issue.
Any suggestions where to look for? I’m out of options.
I’ve 3 Proxmox v9 hosts. All with different CPU types (Intel Xeon, Intel i9 and AMD Ryzen). Among other vm’s, there are 3 guests (Windows 11, OpnSense and OpenWRT) that are running OpenVPN inside them. I’ve created these 3 guests to see if the issue is OS related.
The issue is that once OpenVPN is active inside the vm, it’s internet throughput is only 250Mbps when the guest resides on 2 of the 3 hosts. As soon as I disconnect the VPN, throughput is back to its normal 700-800Mbps. When I migrate the guest to the host with the Intel i9 CPU, the VPN speed is almost the same as the speed without VPN, around 700Mbps.
I’ve checked all settings: MTU, disabled offloading in the guest, changed cpu type to ‘host’, tried different nic types, changed the host nic, but nothing helps. Only on the Intel i9 host, throughput is normal, on the others it’s only one 3rd.
Also changing the VPN type inside the guest doesn’t help.
All hosts are connected to the same network switch.
My guess is that it’s some sort of host configuration/issue, because migrating the vm to one specific host solves the issue.
Any suggestions where to look for? I’m out of options.
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