10gb network card, unstable connection speed

[nmills3]

Hi, i just installed a new 10gb network card in my unraid server and have a matching card in my pc but for some reason my actual network speed is bouncing around a lot. i'm using iperf3 to test and it will start of at about 4gb, then over the course of the test it will slow down to under 1gb. Previously i was using a 2.5gb nic in my server and i was able to get a stable 2.5gb using that, so i'm unsure what's gone wrong here

tower-diagnostics-20220609-1121.zip

[JorgeB]

Jun  9 11:21:41 Tower kernel: ixgbe 0000:01:00.0 eth1: NIC Link is Down

Jun  9 11:21:44 Tower kernel: ixgbe 0000:01:00.0 eth1: NIC Link is Down

Jun  9 11:21:45 Tower kernel: ixgbe 0000:01:00.0 eth1: NIC Link is Down

Link is constantly going up and down.

[nmills3]

is there any reason the link would keep going down like that? did i configure something wrong?

[JorgeB]

That doesn't look like a configuration issue, most likely cable, NIC, transceiver, switch, etc

 

 

[nmills3]

well i guess i new get to find out what doesn't work. would you say that as i have a second of the same card running to the same switch that i can probably say the switch isn't the issue?

[nmills3]

i think i fixed my issue. I switched the two cables plugged into the switch end and now it works. maybe it just wasn't quite in properly or something. but it now seems to work

[MAM59]

Cables are the major point of failure when it is about 10Gbe and UTP.

Note that you can buy quite a lot of "Cat.7 raw cables", but still only a handful of plugs that are capable of doing stable 10G.

Sadly, they are optically almost identical, but you can tell a difference, if you put them in. The bad cables dont lock in properly, you can move them a bit forward and backwards. The real ones snap in and are totally fixed in place.

I spend a lot of try&error buys before I gave up and switched over to fiber (which is rock solid!). Funnily the best working utp cables I found came from Amazon, search for "CSL - 0,5m Cat 7 Netzwerkkabel Gigabit Ethernet LAN Kabel - Baumwollmantel - 10000 Mbit S - Patchkabel - Cat.7 Rohkabel S FTP Pimf Schirmung mit RJ 45 Stecker - Switch Router Modem Access Point".

But be aware, that if you go over 30m in length, its more or less a coin toss. Stay below 10m if possible.

 

[nmills3]

for anyone that finds this post in the future. this issue was my transceivers. i was using direct attach 10m copper cables and my switch didn't like them. Swapping to optical transceivers fixed the problem