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How many network adapters do I need?

    Question

  • I finally got approval for some new hardware, and I'm going to be setting up my first Hyper-V cluster. So I'm reading up on how to set everything up and I'm a little confused on networks. I have set up clusters before, and you usually need a public network for regular traffic and a private network for cluster heartbeat traffic, etc. But it seems like Hyper-V clusters are somewhat more complex:

    Network adapters. For each node of the failover cluster, use more than one network adapter and configure at least one network adapter for the private virtual network. We recommend that you configure a dedicated private network with Gigabit speed for live migration traffic, and this network should be separate from the network for private communication between the cluster nodes, from the network for the virtual machine, and from the network for storage.

    I just want to make sure I'm getting this right in the planning phase. So as I understand it, I should have the following:

    1 network for "regular" network traffic, the network that the physical machines will register in DNS and the VMs will use
    1 network for private cluster communications
    1 network just for Live Migration
    1 network for storage (which I assume is just for iSCSI, I'll be using FC SAN)

    Is that correct? So in my case I would need three network adapters in each clustered machine?

    UPDATE: Just saw this, also: Each node must also have a network adapter that carries Cluster Shared Volumes communication. So is that another separate network adapter? Also, which of these are private (with no default gateway) and which are not?

    Friday, April 23, 2010 6:49 PM

Answers

  • Aubrey,

    I went through the same layers of confusion you're in as I was preparing for my Hyper-V cluster. Most of the documentation I found wasn't as complete or as detailed as I wanted, and the terms used for the various types of traffic within the cluster (cluster communications, Live Migration, CSV) weren't always clear to me.

    On the whole, I'd say you're on the right track. Here's what I finalized for my cluster:

    7 network interfaces assigned as follows:
    2 dedicated to iSCSI (MPIO)
    2 Teamed for the Hyper-V virtual network
    1 cluster communications (heartbeat and CSV)
    1 live migration
    1 host management

    Here's a helpful page I wish I had seen when I was still in the planning stages, hopefully it will help you with your thought process.

    http://technet.microsoft.com/en-us/library/ff428137%28WS.10%29.aspx

    Cheers,

    Greg

    • Marked as answer by Aubrey Friday, April 23, 2010 10:31 PM
    Friday, April 23, 2010 8:03 PM

All replies

  • Aubrey,

    I went through the same layers of confusion you're in as I was preparing for my Hyper-V cluster. Most of the documentation I found wasn't as complete or as detailed as I wanted, and the terms used for the various types of traffic within the cluster (cluster communications, Live Migration, CSV) weren't always clear to me.

    On the whole, I'd say you're on the right track. Here's what I finalized for my cluster:

    7 network interfaces assigned as follows:
    2 dedicated to iSCSI (MPIO)
    2 Teamed for the Hyper-V virtual network
    1 cluster communications (heartbeat and CSV)
    1 live migration
    1 host management

    Here's a helpful page I wish I had seen when I was still in the planning stages, hopefully it will help you with your thought process.

    http://technet.microsoft.com/en-us/library/ff428137%28WS.10%29.aspx

    Cheers,

    Greg

    • Marked as answer by Aubrey Friday, April 23, 2010 10:31 PM
    Friday, April 23, 2010 8:03 PM
  • Heh, that's the page I was quoting from that confused me :)

    I can scrap the iSCSI nics, and we don't do teaming, so it looks like I'll need 4. You can't do host management and have the virtual network on the same NIC? Can they at least be in the same subnet? All our servers are in a single /24.

    Friday, April 23, 2010 8:47 PM
  • Although you can share a NIC between the virtual network and the host, you'll be better off in the long run if you dedicate a NIC to each. The virtual network and host management don't necessarily need to be in the same subnet, but it's not a problem if they are. The cluster-dedicated NICs should be in separate subnets. I have them directly connected to each other via crossover cables.

    Check out this blog entry, you may find it useful down the road:

    http://blogs.technet.com/iftekhar/archive/2010/01/18/microsoft-virtualization-hyper-v-live-migration-network-configuration.aspx?CommentPosted=true#commentmessage

     

    Greg

    Friday, April 23, 2010 9:05 PM
  • Great, that really helps out. I definitely need them to be on the subnet, we only have one subnet for servers. Thanks again, now I know how many NICs to order on the servers I'm about to buy.
    Friday, April 23, 2010 10:33 PM
  • Hi Aubrey,

    When it comes to adding NIC's to virtual machine sit is always best to have several physical nics allocated for that purpose. As CUPressIT mention long run you'll identify some VPC's will require more network bandwidth than other virtual pc' where as you might have to dedicate  physical NIC for that.


    NIC teming is good but it'll be out of Microsoft point of view and you'll need to rely on NIC card manufacures software for that. Out of the box Microsoft doesn't solution for that. Some aditional information about this can be foudn over here published in Microsoft web site (http://blogs.technet.com/virtualization/archive/2009/03/02/hp-whitepapers-on-nic-teaming-for-hyper-v.aspx)

    good luck with your deployment!

    Sunday, April 25, 2010 2:15 AM