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Virtual Switch advice

Unanswered Virtual Switch advice

  • Tuesday, January 29, 2013 3:03 PM
     
     
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    Could somebody please confirm for me the way the new 2012 Server virtual switch works and the best config?

    I have a server with Quad 1GB NIC, all are on-line and connected to a Cisco switch running LACP.

    If I configure a single VM and use a virtual switch, what is the performance I can expect to get?

    For example, will the virtual switch load balance across multiple incoming and outgoing connections to ensure all 4 x 1GB ports are utilised?

    I am planning on testing this with a file server running in a VM and want to see what performance I will get compared to our old stand-alone file server with 1 x 1GB NIC.

     

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  • Thursday, January 31, 2013 8:41 AM
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    Hi,

    > will the virtual switch load balance across multiple incoming and outgoing
    > connections to ensure all 4 x 1GB ports are utilised?

    That’s depends on how you configured Virtual Network for Hyper-V Virtual Machine.

    When we create a virtual External network, we should specify a Physical NIC, this physical NIC will be used as a network switch and connect to physical network. Instead system will create a virtual network switch adapter, which works as the original physical NIC in the Hyper-V host.

    > what is the performance I can expect to get?

    Of course, virtual NIC performance will not exceeded the performance of physical NIC. But you can get better virtual nic performance through following methods:

    • Ensure guest operating systems are configured to use a “Network Adapter” as opposed to a “Legacy Network Adapter.”
    • Configuring all the virtual machines to use a single physical network adaptor, configure groups of virtual machines to use virtual networks, and configure each virtual network to use a different physical network adaptor. This configuration helps spread the network traffic across multiple network adaptors.
    • Uncheck “Allow management operating system to share this network adapter” option in Hyper-V network configure, the option isolate the physical NIC from the host server.
    • In Windows Server 2012, you can create network teaming, and then you can specify the teamed network adapter as external network.

    For more information please refer to following MS articles:

    Optimizing Performance on Hyper-V
    http://technet.microsoft.com/en-US/library/cc768529(v=BTS.10).aspx
    Hyper-V: Virtual Networking Survival Guide
    http://social.technet.microsoft.com/wiki/contents/articles/151.hyper-v-virtual-networking-survival-guide-en-us.aspx
    NIC Teaming Overview-Windows Server 2012
    http://technet.microsoft.com/en-us/library/hh831648.aspx

    Lawrence

    TechNet Community Support

     
  • Thursday, January 31, 2013 11:00 AM
     
     
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    Hi Lawrence

    Thanks for the detailed response.

    Since my original post I have configured server 2012 Teaming across all 4 NIC's. Then created a Virtual switch using this NIC Team.

    I have some good news, I have managed to get > 3Gbs throughput on the Virtual Switch (Both in and out) with the following config:-

    1. Ensure SV-IOV is enabled in BIOS (It wasn't as default)
    2. Create a Team in Windows Server utilising all 3 NIC's. Teaming mode: LACP, Load balancing mode: Address Hash, no standby adapters
    3. Ensure Cisco switch configured for the correct ports with LACP
    4. Create virtual switch with external, 'Microsoft Network Adapter Multiplexor Driver', Allow management o/s to share this network adapter and SR-IOV on.

    With a VM I then created, pointed to the Virtual Switch, I created a share and did some testing from 2 PC's with 1Gb network connections and also from 4 PC's concurrently. One test achieved all 4 PC's downloading large files from the server at 113Mbs each and the server NIC showing 3.8Gbs being sent :)

    Obviously it does depend a bit on the switch routing incoming traffic to different ports when sending data to the server and occasionally it did only use 2 of the ports. But once you have 50+ PC's doing this I'm sure it will work better.

    I may consider a dual 10Gb NIC for the server next time I purchase a new switch. (Probably later this year)

    I will read the links you posted as well.