Windows 2008 R2 with HyperV having big network problems RRS feed

  • Question

  • I have a Windows 2008 R2 Enterprise Server with HyperV. I created a Virtual Machine running Windows 2008 R2 Standard.
    I have a second physical computer running Windows 2008 Enterprise, where I opened 2 command prompts; from one command prompts I run ping -t <Win2008 R2 host> and from the other one I run ping -t <Win2008 R2 VM>. The 2 ping get the expected responses in less than 1 ms

    From the Win2008 R2 VM I run wbadmin start systemstatebackup -backuptarget:\\<Win2008 server>\Share\

    Pretty soon after the backup starts, the pings start failing: while there are some successful responses (some of them after quite long time, like 1500 ms), most of the returns are either Request timed out or Destination unreachable;
    On the VM, wbadmin was able to find all files (~72K) and it repeatedly displays Found <72k> Files (the same number).
    I can see also see that the VHD files on the are slowly growing but the pings do not improve at all.

    I have disabled the TCP chimney and RSS on all 3 OSes hoping that this fixes the problem but it does not.

    This seems to be a problem with the Virtual Adapter created by Hyper-V but it may be a bigger problem in Windows 2008 R2, considering my post from

    After not getting any feedback on the post from above, I opened a case with Microsoft; so far their claim is that the problems come from networking level and they are analyzing NetMon traces now.

    Has anybody had similar problems?

    Friday, November 13, 2009 10:20 PM

All replies

  • It seems like the problem is caused by the virtual adapter created by Hyper-V after all.
    I removed that adapter, then stopped Hyper-V and I ran wbadmin to backup the host's system state to the same network share (as in the original test, from VM) and it looks like the network connection between the 2 computers is stable.

    Saturday, November 14, 2009 3:27 PM
  • Hi Anonymous!

    I am having exactly the same problem here.  Windows 2008 R2 with Hyper-V.  I first I thought the problem was just with the guest OS, I have a guest and start doing a ping -t for a while.  Most of the time got succesful replies but sometimes I get requests time outs (the other day got time outs for almost two hours).  Connectivity is lost on the guest while this happens.

    Then I discovered that the host was having issues too, like not finding domain controllers on the network, failing to connect to shares, etc.  It is frustrating because the problem does not happen all the time.  Everything started happening after I installed Hyper-V, I followed all MS documetns to deploy this, so no mistake on my part as far as  I know.

    Did you find a solution other than uninstalling Hyper-V?  This is our VM host and that is the role we need on this server.

    I appreciate your feedback.  Thanks!

    Monday, May 10, 2010 4:42 PM