I/O: The Next Standards Battleground

The PCI Special Interest Group, or PCI-SIG, as it's more commonly known, is making a serious power play with the combo of PCI virtualization technologies Single Root IOV (SR-IOV) and Multi-Root IOV (MR-IOV) plus the PCI Express 3.0 standard. Via the Gen 3 standard and both single-root and multiroot I/O virtualization support, PCI-SIG is looking to become the premier, de facto standard for I/O virtualization.

And why not? An easy-to-use, industry-standard I/O virtualization specification coupled with an updated transport mechanism capable of accommodating huge I/O streams is a powerful vision.

The main thing standing in the way is challenges from companies, such as Xsigo, that are delivering proprietary IOV with InfiniBand for transport. PCI-SIG is trying to stomp out this competition and create a standard for IOV before anyone has a chance to grab major market share. Virtensys and NextIO both use the PCI-SIG SR-IOV standard and PCIe interconnects, and many other vendors are working on revising their system architectures to incorporate the new standards. Though it won't happen overnight, it's only a matter of time until all the major hardware makers offer PCI Express Generation 3 servers. That's great news for IT because PCI-SIG envisions a world of graphics, storage, network and other I/O interconnects served up virtually with SR-IOV and transported by the updated 128-Gbps PCI Gen 3 standard. SR-IOV allows multiple virtual PCI devices to be presented over a standard PCI interface. This interface could be switched via PCI and deliver dozens of virtual PCI Express adapter cards of all sorts to virtualization host servers.

What about blade servers, which can't accommodate individual PCI interfaces? MR-IOV allows all of the virtualization goodness of SR-IOV to be extended to consolidated hardware platforms like blade chassis where individual boxes can't have independent adapters.

The independent I/O virtualization industry is stoked about the IOV specification set, and while vendors have produced valid platforms without using PCIe as the transport mechanism, I'm glad to see hardware makers joining in. Now, SR-IOV and MR-IOV both require support at the BIOS and operating system level (hypervisor, in the case of virtualization host servers), so it's not like magic. However, the standard provides a common way of doing things that's very compelling and really ready for use.

Has PCI-SIG pushed its vision to market fast enough to head off proprietary competition? The next few months will tell for sure. IT shops that care about standards may want to keep a close eye.

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