Slow connection speeds on VM or LXCs

[subjectx]

Hi,

I have 2x 1GBit connections in LACP mode.

I'm getting download speeds on VMs and LXC at around 200MBits/s, rarely around 300MBits/s, even from servers in the same local network, on 10GBit links, switches are all 10GBit.

How can one start debugging this? What kind of benchmarks should I do?

 

[aaron]

What model is set for the NICs of the VMs?

I would start by running iperf between some servers on the network. On the PVE Host and then inside the VMs to locate where a bottleneck might be. Make sure that the load on the network is low when doing this to avoid unexpected different results caused by other services using the network during the benchmarks.

 

[subjectx]

VMs have VirtIO, you think that could a culprit? Will test with different NICs then.

Will also do ipref, I have two identical server on same switch. Thank you for now.

 

[aaron]

VMs have VirtIO, you think that could a culprit?

No, that is actually the best option for performance. But a few tests on different levels should help to see what is possible and where performance is lost.