X520-DA2 slow upload speed

[velik0ff]

Hello,

I am struggling with slow download speed for a couple of weeks now with an X520-DA2 with RJ45 transceivers. Usual upload speed before the Proxmox machine is around 600MBit/s. I tested with speedtest-cli and I get around 30MBit/s. I tested with a second NIC which is the X540-T2 directly with RJ45 and the problem does not exist, I get the usual 600MBit/s. (both tests were ran on the same speedtest servers)

I have the 10GTek sfp+ transceivers which are tested on another X520-DA2 months ago and they were working perfectly fine on a pfSense firewall.

Any help and suggestions would be greatly appreciated.

 

[velik0ff]

Just in case anyone stumbles upon the same issue with DA cards with RJ45 transceivers, I am writing this comment as a possible solution.

After a lot of testing to find out where the issue was, I narrowed it down to the fact that the X520-DA2, does not support auto-negotiation and pfSense in Proxmox does not handle this as it is on it's own because of the virtual devices.

My initial thought was that if I change the E1000 instead of the VirtIO for pfSense will limit the bandwidth and the upload speed will go to normal. My expectations were successful as when I changed to E1000 my uploads speeds after pfSense jumped by a lot.

However, this solution was not optimal, so I decided that I need an SFP transceiver that limits the internet bandwidth to 1000MBit/s (which is the maximum for my ISP currently) and this will give more performance for less power and heat.

Ordered the transceiver, swapped it and the performance is as expected for both download and upload speeds, heat cannot compare to the heat outputted from the 10G transceivers, however I kept my 10G transceiver for my LAN interface as I have my WiFi access points connecting with 10G ports.