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I/O virtualization: Approaches and implementations

Learn which companies have offerings in the I/O virtualization space, how they approach network infrastructure problems, and the pros and cons of each product.

There's a lot of hardware with lots of processing power in today's data center and, as a result, a server I/O bottleneck problem and a glut of cabling to support all of the hardware. I/O virtualization promises to solve the problem, but there's no consensus on the best approach. The PCI Special Interest Group (PCI-SIG) has offered up two I/O virtualization specifications to help standardize I/O virtualization implementations, but vendors for the most part are developing products independent of the standards.

With those kinds of dynamics at play, you'll need to study the landscape closely before wading into an I/O virtualization project. Check out our tutorial to find out about the approaches different vendors are taking to I/O virtualization, the pros and cons of each product, how I/O virtualization differs from Fibre Channel over Ethernet (FCoE) and how the PCI-SIG standards work.

I/O virtualization products, standards reduce network infrastructure headaches
Virtualization and blade server technologies have enabled a generation of consolidated computing devices capable of cramming extraordinary computing power into smaller form factors. But the increased processing power per square inch has brought about a new I/O problem: The pipes can't move data fast enough to keep up with today's processors. To address that problem, new I/O virtualization products and standards are emerging to extend PCI Express (PCIe) pathways to separate I/O devices. This allows multiple physical servers and virtual machines (VMs) to share I/O resources.

Xsigo's I/O virtualization approach: Software virtualization via I/O Director
Xsigo Systems Inc.'s approach to I/O virtualization is similar to Microsoft Corp.'s and VMware Inc.'s server virtualization methods. Xsigo's VP780 I/O Director consolidates multiprotocol I/O server traffic via high-speed InfiniBand links. This software I/O virtualization approach -- one of two basic methodologies -- heavily favors server virtualization environments. Jon Toor, Xsigo's vice president of marketing, said that approximately 90% of the company's 60 or so production deployments are virtualized server environments, mostly VMware shops.

Alternative approach to I/O virtualization: PCIe bus extenders
While Xsigo Systems Inc., takes a software virtualization approach to I/O virtualization, the majority of vendors in the I/O virtualization space take a different path – implementing on the server a PCI Express (PCIe) bus extender to a "card cage" device that houses standard, off-the-shelf I/O cards and adapters. This method has been adopted by companies such as Aprius Inc., NextIO Inc. and VirtenSys Inc.

I/O virtualization and Fibre Channel over Ethernet (FCoE): How do they differ?
Since I/O virtualization and Fibre Channel over Ethernet (FCoE) technology both aim to reduce the physical infrastructure at the server/network interconnect, users may be confused about how Cisco Systems Inc.'s Unified Computing System (UCS) and FCoE support in the company's Nexus switches play in this space. In addition, many IT organizations may find the choice between the Xsigo Systems Inc. and PCIe approaches a difficult one.

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