Slow network in Virtual Machines on Hyper-v 2012R2

By | March 9, 2014

While working on a Hyper-V project I was noticing that the virtual machines had very sluggish network performance. This was a brand new enviroment with a good bandwidth so therefore I was a bit stumped on why the Network was acting so sluggish.

After doing some testing we saw that the hyper-v host had about 100mbit access to the internet and low latency on the link. The virtual machine that was running on it with a shared network card has about 1/3 of the speed and was getting quite high latency when accessing the internet.

After playing around with the Network driver I tried disabling VMQ on the card and voila! everything worked perfectly. When I saw it was a Broadcom driver and did a quick google search I found that there is a known issue with Broadcom network adapter drivers and VMQ

You can read more about it here –> http://support.microsoft.com/kb/2902166

So if you are having trouble with virtual machines and sluggish network performance with Broadcom drivers, try disabling VMQ Smilefjes

NOTE: I had added the latest Broadcom drivers to the hyper-v host but they did not fix the issue, I contacted Broadcom which gave me a hotfix which I used in this instance.

4 thoughts on “Slow network in Virtual Machines on Hyper-v 2012R2

  1. Håvard

    I believe this was fixed in a driver update last year? Did you use the latest Broadcom drivers?

    Reply
    1. msandbu Post author

      Hi Håvard,

      thanks for the feedback, i’m updating the blog as we speak. But in this case I needed to obtain a hotfix from Broadcom since the latest drivers did not fix the issue.

      Reply
  2. Chris

    Instead of disabling VMQ I would recommend to install the latest Broadcom firmware and drivers; that will fix the VMQ issue. Latest Broadcom firmware and drivers can be obtained through support pages of your server manufacturer; in my case DELL.

    Reply
    1. msandbu Post author

      Hi Chris,

      thanks for the feedback, im updating the blog as we speak. But in this case I needed to obtain a hotfix from Broadcom since the latest drivers did not fix the issue.

      Reply

Leave a Reply

Your email address will not be published. Required fields are marked *