SR-IOV Support in the Next Version of Hyper-V

While browsing my list of RSS feeds tonight, I came across a series of articles by John Howard, a senior program manager on the Hyper-V team at Microsoft. The post was one of a series of posts describing SR-IOV support in the next version of Hyper-V, found in Windows “8″. I hadn’t heard that Microsoft was adding SR-IOV support to the next version of Hyper-V, so when I saw that I was surprised. Personally, I think SR-IOV support is a big deal (see the note at the end of this post for why).

If you’re not familiar with SR-IOV, I suggest you read this quick SR-IOV tutorial I published on this site in late 2009.

Here are the links to John’s SR-IOV in Hyper-V posts:

Everything you wanted to know about SR-IOV in Hyper-V, part 1
Everything you wanted to know about SR-IOV in Hyper-V, part 2
Everything you wanted to know about SR-IOV in Hyper-V, part 3
Everything you wanted to know about SR-IOV in Hyper-V, part 4
Everything you wanted to know about SR-IOV in Hyper-V, part 5

It’s great to see Microsoft adding SR-IOV support to Hyper-V; this brings SR-IOV out of the niche Linux market and into a broader, more mainstream market. This also applies some competitive pressure against market leader VMware, who now has to respond in some fashion—either by adding SR-IOV support to their ESXi hypervisor, or by explaining why SR-IOV support isn’t necessary. Personally, I hope that VMware does the former and not the latter.

(By the way, for those of you wondering why SR-IOV is important, there are lots of potential synergies here—in my view, at least—between hardware switching on an SR-IOV NIC and things like software-defined networking.)

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  1. Louw Pretorius’s avatar

    Hi Scott,

    Could you elaborate on the use-case for SR-IOV in VMware environments. As I understand it VMware standard Network Port-groups can have up to 4088 ports while with SR-IOV networking – in principle – up to 512.

    Is there a FC use-case that might be more useful?


  2. Sriram’s avatar

    Hi Scott,

    Assuming VMware does support SR-IOV on ESXi, what do you think will be the impact on the virtual networking support already existing within the VMware Hypervisor?

    Appreciate further pointers.


  3. slowe’s avatar

    Louw, Siriam, I responded to your questions in this blog post:

    Thanks for your comments! Feel free to keep the discussion going either here or in the comments on the other post.

  4. Chris Hurson’s avatar

    Wow, this is major.

    Makes XS a little less compelling…

  5. slowe’s avatar

    Chris, stupid question here—where does XenServer stand with SR-IOV support?

  6. Chris Hurson’s avatar

    Not a stupid question at all, and glad to save hours of Googling.

    XenServer is based on a standard linux implementation, and /proper/ support for SR-IOV has existed in the linux kernel since about 2.6.35.

    Of course, the hardware must support it, and the feature must be implemented in the hardware driver. Linux kernel drivers with basic – if dicey – support for SR-IOV were introduced for Intel 82576 and Intel 82599 (the only hardware i can speak to, in this context) in kernel 2.6.30 and ~2.6.34, respectively (don’t cite me, but it’s about right). So basically, both Red Hat and Citrix have had some form of SR-IOV support since 2009.

    Support has become mature, since then.

    While the following link is Provisioning Services-centric, it addresses SR-IOV tidily and explains its limitations with respect to failover, etc.:

    I hope this helps. Great blog you have!

  7. slowe’s avatar

    Thanks for the additional information, Chris—much appreciated!


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