Very poor network performance on vmbr

[luminarycrush]

Hi, I'm evaluating whether to use Proxmox on a KVM server I'm setting up, and I'm getting some discouraging network performance results.

On the default vmbr0 interface setup during install, copying ISO files over the network to the server is trickling in at 110KB/s. When use a physical interface I get 9.6MB/s. What gives? I'm using scp to copy - no NFS, etc.

The motherboard has a realtek interface card, but based on complaints about that card's driver I tried a broadcom PCIE card. It has the same poor performance when using the virtual bridge, but works good as a physical NIC.

Any thoughts?

Thanks.

 

[mechanicus]

I don't know, what you do and what you mean. The vmbr0 is your physical interface, it has the same mac address as your eth0.
Your network interface seems to be an old 100 Mbit/s one. 1gbit/s cards has appr. 60-70 MB/s throughput (depending from the server).
May be the network chip on the motherboard is not correct set in the bios?

 

[luminarycrush]

This is a new motherboard and new NIC cards & yes they are all 1Gb. The SCP transfer goes through another device which is 100Mb, so please ignore any misleading info about why it seems slower overall than a gigabit line should provide.

The point is that when I use the ETH device I see ~10MB performance, but when I use the VMBR device I see ~110KB for the same transfer from the same host. Something in the VMBR alias appears to be slowing down the network speed.

The test was done first with the VMBR interface, from the console, as configured during the installation. After seeing very poor performance I downed the VMBR pseudo interface, assigned the same IP to the parent ETH interface, flushed the routing table and reset the default route. The difference is what I wrote above.

Any thoughts?

 

[luminarycrush]

OK, I found the problem to be the Realtek NIC - the first test I ran I somehow didn't clear out the route and the VMBR on that NIC was still being used as the default route. It works fine on the Broadcom NICs.