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6 Replies Latest reply: Oct 17, 2012 1:58 PM by user12273962 RSS

Which is better for VM network throughput?

Looney128 Newbie
Currently Being Moderated
Want to get some opinions on this....

I want to offer the network to the VM that I have, but I would like to increase the throughput.
I could bond two ports together on the VMS, but I have read in other post this will give redundancy, but may not give higher throughput.
The Windows VMs I have will probably have gig nics??? so even if I do have bonded ports, will I still be capped at 1Gbps on the VMs vNIC?
OR do I just set up two VM networks...attached to the same vlan and set the VMs to have two NICS, then team them??

Any Thoughts
  • 1. Re: Which is better for VM network throughput?
    budachst Journeyer
    Currently Being Moderated
    I touched on that only briefly on the other post, so I'll try to sum that up a bit. LACP bonding will, per nature, broaden your network path, but not speed it up per se. Just think of a two-lane freeway instead of a one-lane freeway. You will be able to shove the double amount of cars over the freeway, but all cars will not go faster than 80mph.

    Since one single connection over a LACP bond will only run at Gbit speed, you won't get transfer speeds higher than Gbit to and from your VMs. However, you might be able to get 2 x 1 Gbit connections concurrently to and from your VM.

    Now comes the exception: there are options to balance the traffic round-robin, but only for special services. This is what multipathd is capable of. I have a bonded LACP connection as my VM network and I am able to get write speeds to my iSCSI targets, mounted inside my VMs from 170+ mb/s, since multipathd passes the traffic round robin to my LACP interfaces. You will have to fine-tune a couple of tcp and iSCSI parameters to achieve maximum performance, but it can be done.

    It will be much easier to install a 10 Gbit ethernet card, though…. The question will be, is such a high performance setup mandantory or not…
  • 2. Re: Which is better for VM network throughput?
    user12273962 Pro
    Currently Being Moderated
    What he said except..

    Where possible use jumbo frames. You'll get alot more data throughput with jumbo frames. 3.1.1 is the first Oracle VM release to support jumbo frames but there is a bug on using jumbo frame on 10gb.

    Edited by: user12273962 on Oct 16, 2012 12:23 PM
  • 3. Re: Which is better for VM network throughput?
    Looney128 Newbie
    Currently Being Moderated
    I am not blessed with having a 10GB switch..... :-(
  • 4. Re: Which is better for VM network throughput?
    Looney128 Newbie
    Currently Being Moderated
    Never thought of teaming nics on a VM to the same network within virtual land. That may be the solution....
  • 5. Re: Which is better for VM network throughput?
    budachst Journeyer
    Currently Being Moderated
    Can you provide some numbers on the difference running with jumbo frames vs. without? I never noticed much difference when using jumbo frames on my iSCSI hosts.
  • 6. Re: Which is better for VM network throughput?
    user12273962 Pro
    Currently Being Moderated
    It depends on what type of data you're moving. If its small datasets at random times... NO. You will not see anything. If you're using hung amounts of data.... say..... in a "sequential reads and "sequential writes".... Yes. You will see a difference. It shows up even more when it comes to saturated links.

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