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Virtualization tools and stuff. By Matthijs ten Seldam

Windows Server 2012 Hyper-V and SR-IOV

Windows Server 2012 Hyper-V and SR-IOV

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With Windows Server 2012 Hyper-V we’ve taken performance to the next level.

For example:

  • Up to 64 virtual processors
  • Up to 1 TB memory per VM
  • > 1 million IOPS per VM?
  • >10 Gb/E within a VM?

 

Windows Server 2012 Hyper-V provides Single-Root Input/Output (SR-IOV) Networking.

To learn more, I want to point you to this outstanding 8 part blog series written by John Howard. John makes a small joke that this is a feature the team has been working on for many years and it merely appears in the UI as a few checkboxes.(!) While the UI impact may appear minimal, the development and test behind SR-IOV requires deep engineering prowess which will become evident as you read this blog. I’ve included brief descriptions of each part with links below, but I highly recommend the entire series.

I also want to highlight one very important point about Windows Server 2012 Hyper-V and SR-IOV. Our awesome team didn’t take any shortcuts. Specifically, using SR-IOV with Hyper-V 2012 works with Live Migration. I know that everyone has come to expect that all our new Hyper-V features work with Live Migration, but this feature is very different because:

>>  the virtual machine is actually communicating with physical hardware  <<

Yes, think about that for a second.

When you go into Device Manager of the guest OS running within a VM configured with SR-IOV, you’ll actually see the real NIC. Here’s a screenshot. This is Device Manager on a virtual machine with Windows Server 2012 as guest and SR-IOV enabled using a Broadcom NIC:

clip_image001

It’s one thing to Live Migrate a virtual machine where the VM and all of its devices are virtualized, it’s another to Live Migrate a virtual machine where the VM is communicating with hardware.

Windows Server 2012 Hyper-V and SR-IOV support with Live Migration is a really, really big deal and another area where VMware is attempting to catch up with us. (No, vSphere 5.1 can’t vMotion VMs with SR-IOV…).

One more thing, SR-IOV also applies to Microsoft Hyper-V Server 2012, available at no cost.

 

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“Everything You Wanted to Know about SR-IOV in Hyper-V” by John Howard

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Part 1: http://blogs.technet.com/b/jhoward/archive/2012/03/12/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-1.aspx

Part 1 discusses emulated versus software devices, the pros and cons and constraints of each and why Microsoft is investing in SR-IOV.

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Part 2: http://blogs.technet.com/b/jhoward/archive/2012/03/13/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-2.aspx

Part 2 discusses the SR-IOV standard, physical functions (PFs) virtual functions (VFs) and the hardware requirements to make SR-IOV even possible.

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Part 3: http://blogs.technet.com/b/jhoward/archive/2012/03/14/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-3.aspx

Part 3 discusses device drivers and how they function in an SR-IOV environment as well as screenshots of an SR-IOV NIC within a Hyper-V VM.

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Part 4: http://blogs.technet.com/b/jhoward/archive/2012/03/15/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-4.aspx

Part 4 discusses some of the low level necessary firmware and motherboard changes to make SR-IOV function and provides a pointer to an interesting presentation given 4 years ago at WinHEC 2008 by Jake Oshins that provides further insight into SR-IOV.

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Part 5: http://blogs.technet.com/b/jhoward/archive/2012/03/16/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-5.aspx

Part 5 explains the IO path with SR-IOV enabled, covers SR-IOV configuration via the UI and a deeper dive into PowerShell.

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Part 6: http://blogs.technet.com/b/jhoward/archive/2012/03/19/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-6.aspx

Part 6 discusses SR-IOV and Live Migration in detail. It covers the engineering challenge of making SR-IOV work with Live Migration (not trivial folks) and even includes a video that demonstrates a virtual machine with an SR-IOV NIC under load being Live Migrated. There’s even a link to a WinHEC 2006 presentation (told you we’ve been looking at this technology a while…)

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Part 7: http://blogs.technet.com/b/jhoward/archive/2012/03/20/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-7.aspx

Part 7 discusses SR-IOV and how it works with the new inbox Windows Server 2012 NIC Teaming. Yes folks, you can team SR-IOV NICs in the guest.

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Part 8: http://blogs.technet.com/b/jhoward/archive/2012/03/21/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-8.aspx

Part 8 discusses debugging SR-IOV and includes examples in PowerShell and covers troubleshooting through the Event Viewer.

Comments
  • Any Microsoft Plans for GPU pass-through so that we can one day run AutoCAD in Virtual machines without a problem ?

  • This can also be done on kvm with fail over bonding at the VM. Upon migration the sr-iov device is detached and then reattached on the other side. I don't think its as big a deal as you say it is, because MS is basically doing the same thing with hyper-v migration except it is better hidden from the user. SR-IOV doesn't support pcie device state migration so all implementations are going to use this 'trick'. I agree however VMware has fallen behind severely in the last 2 years.

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