Ethernet Bonding - Increasing bandwidth or throughput?

[mhamzahkhan]

Hey everyone,

I'm playing with Open vSwitch right now and was trying bonding working with it.

But, I had a question which I'm a little confused about bonding.

Even without Open vSwitch, and using the stock, Linux bonding module with 802.3ad mode I had the same problem.

From what I have read about bonding, it seems like if you bond (for example) 2x 1Gbit Ethernet connections on two servers (ie so both have two ports bonded), then if using something like 802.3ad, a file transfer should utilize both ports, and you should see a throughput of 2 Gbit/s. So this would be an increase in throughput and bandwidth, right?

But, what I generally see, is for any single TCP connection, only one port is ever utilized at a time.

So for example if I'm SCPing a large file from server1 to server2, I generally see that the scp session is only using one interface, at 1 Gbit/s. I can then also run a second SCP session which will use the second port, and also move at 1 Gbit/s.

This would be increasing the bandwidth, but not the throughput, correct?

Which of these behaviors is what I should be seeing with 802.3ad? I guess it depends on the hashing method? Is there a hashing method which will allow a single connection to be spread over two interfaces, allowing 2Gbit/s transfers?

 

[mayhem87]

What u are seeing is usually the default behavior and is load balancing per destination. Try seeing if you can do per packet but this might break something as packets could become out of order.