Hyper-V Update to Boost Network Stability for Virtual Machines

Microsoft has delivered a hotfix designed to resolve an issue in which virtual machines running in Hyper-V on top of Windows Server 2008 R2 are impacted by severe network instability. Customers running ISA Server, IAG, Forefront TMG or Forefront UAG on Hyper-V R2 might have already noticed that the connection between the guest and the virtual switch can be impaired, underperforming to the point where it is lost entirely. The problem can affect the following editions of Windows Server: Windows Server 2008 R2 Datacenter, Windows Server 2008 R2 Enterprise, Windows Server 2008 R2 Standard.

“Consider the following scenario: You install the Hyper-V role on a computer that is running Windows Server 2008 R2. You run a virtual machine on the computer. You use a network adapter on the virtual machine to access a network. You establish many concurrent network connections, or there is heavy outgoing network traffic. In this scenario, the network connection on the virtual machine may be lost. Additionally, the network adapter is disabled,” Microsoft informed.

While an actual update to resolve the issues is not yet available, Microsoft is providing customers with a hotfix to help them make sure that network connectivity will not be affected. The fix in question is designed to take care of exclusively network connection related issues associated with Hyper-V virtual machines that become disconnected under heavy outgoing network traffic. The hotfix can only be deployed on top of Windows Server 2008 R2 installations with the Hyper-V role enabled.

“Apply this hotfix only to systems that are experiencing the problem described [above]. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix,” the company added.