I found the root cause of the issue, and it was related to the NIC chipset.
I was initially using an HPE FLR560, which is based on an Intel chipset X520-DA2 that apparently does not handle VXLAN properly in my setup. As a result, I was experiencing significantly lower network performance.
I replaced the NIC with an HPE FLR562, which uses a newer chipset X710-DA2, and the issue was resolved.
After the change, I was able to achieve around 9 GiB/s of network throughput with VXLAN.
So, if anyone is experiencing similar VXLAN performance issues on Proxmox, it may be worth checking the NIC chipset and its VXLAN/offload support.
I was initially using an HPE FLR560, which is based on an Intel chipset X520-DA2 that apparently does not handle VXLAN properly in my setup. As a result, I was experiencing significantly lower network performance.
I replaced the NIC with an HPE FLR562, which uses a newer chipset X710-DA2, and the issue was resolved.
After the change, I was able to achieve around 9 GiB/s of network throughput with VXLAN.
So, if anyone is experiencing similar VXLAN performance issues on Proxmox, it may be worth checking the NIC chipset and its VXLAN/offload support.