iPerf3 speed between remote and host is slow

diogoribeiro

Member
Feb 9, 2021
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Hi,
So I have a Ubiquiti US-16-150W connected to an Odroid H2+ using two CAT7 cables. I'm using Port 13 and Port 14 on the switch which are "aggregated" as per the following picture:
1612887631201.png

When i run iperf between two VMs speeds are fine:

1612887715674.png

But when i do run the iperf between a computer connected by ethernet to my switch speeds drop significantly:

1612887797518.png

My network configuration is :

1612887829311.png

And I tried passing the interface both by using Virtio and the e1000 (nevermind the Mac Addresses):
1612887884348.png
and
1612887900039.png

With the same results. Considering the Switch is Gigabit and everything is wired i was expecting way higher numbers . Am I doing something wrong?
 
you should use virtio nic, e1000 are too slow.


About lacp, you can't use more than 1 link for 1tcp connection, so you need to use "-P" option to iperf.

also about "bond-xmit-hash-policy" layer2+3 ,
that's the load balancing rules for your tcp connections, layer2+3 = mac-ip address. So if you test between 2 vms, it'll always use same link.
you need to use "layer3+4", to use multiple tcp connections for same ip address. (and -P option in iperf).
This is for the traffic going out your physical nic.

Now , you also need same layer3+4 in your switch lacp config, for traffic going out the switch port, (so coming to destination vm).
 
Hi,
Thanks for your reply. The reason i went with e1000 is that the VM won't acquire IP if i have virtio nic. Never did, even before LACP. Other machines work fine. XPenology image doesnt work. Any hints on where to start troubleshooting?

Thanks.
 
also just to rule it out: did you check the cables? 100mbit are suspicious, it's the speed when you have a partly broken cat5e cable
 

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