Xsigo's I/O virtualization approach: Software virtualization via I/O Director

Learn about Xsigo's approach to I/O virtualization for reducing network infrastructure complexity, including the pros and cons of the company's VP780 I/O Director system.

Xsigo Systems Inc.'s approach to I/O virtualization is similar to Microsoft Corp.'s and VMware Inc.'s server virtualization methods. The Xsigo 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.

Xsigo's software I/O virtualization approach places InfiniBand cards in each physical server and connects those servers to the Xsigo 4U VP780 I/O Director at 20 Gbps per link. The I/O Director presents virtual Ethernet and Fibre Channel (FC) network interface cards (NICs) and host bus adapters (HBAs) to connected standard x86 servers, and traditional Ethernet and FC connections to core networks. The servers see the virtual interfaces as if similar physical interfaces were inside the servers.

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"So you get a massive pipe to the physical server and multiple virtualized I/O ports, virtual NICs and virtual HBAs that you can [use to] slice and dice traffic within that giant pipe," said Jeff Boles, senior analyst and director, validation services at Hopkinton, Mass.-based Taneja Group.

The main benefits of Xsigo's model are reduced physical infrastructure and flexibility. Only one card and one cable are required for any server connection to the I/O Director (two are standard for redundancy), instead of at least one cable per I/O interface. That's a lot fewer cards and a lot less cabling, especially when you have to add or replace cards, not to mention less power and cooling.

Greg Schulz, founder and senior analyst at StorageIO Group, a Stillwater, Minn., research and consultancy company, positioned Xsigo's approach as a way to move toward data center convergence without an investment in Fibre Channel over Ethernet (FCoE) gear. "Xsigo's benefit today is that their HBAs can plug into your existing PCIe slot and give you Fibre Channel and converged Ethernet functionality capability as an alternative to buying Brocade [Communications Inc.] FCoE, QLogic [Corp.] FCoE, Emulex [Corp.] FCoE or Cisco [Systems Inc.] FCoE, while also simplifying your cabling," he said.

Wholesale Electric Supply Co. of Houston Inc. implemented two VP780 I/O Directors when it deployed a VMware ESX Server environment earlier this year. Bill Fife, the company's director of IT, described the benefits: "We've reduced the hardware, collapsed the network, reduced the power demand, and we have a highly flexible, highly available environment. I can add and reconfigure virtual NICs and virtual HBAs from almost anywhere I can access the network. We have considerable room for growth with just the current hardware."

Fife said he's happy with the system's ease of administration and increased data throughput. "We don't have significant numbers of networking components, and we don't have a lot of cards in the servers, so data moves faster than in our previous environment," he said.

Taneja Group's Boles said the advantages of Xsigo I/O Director are multiplied in virtualized server environments, especially for moving virtual machines (VMs) and workloads between physical servers.

"In a virtualized data center, that flexible fabric becomes much more important because all of those virtual NICs can be tied to your virtual servers," Boles said. "You can create this virtualized network that follows your virtualized server infrastructure around regardless of what kind of changes you make."

Pricing for each I/O Director starts at $30,000 and includes a 24-port chassis, 1.5 terabytes per second (TBps) of available bandwidth, basic tech support, software and operating hardware (the cards that connect the cables from the servers and the cards that connect to the core networks). Xsigo offers the IS24 Expansion Switch with 24 ports starting at $7,500 each. Xsigo Systems' Toor said his customers' typical deployments include two I/O Directors for redundancy, six expansion switches that support up to 120 servers and upgraded tech support. This typical deployment costs approximately $125,000.

Boles said the drawbacks to the Xsigo approach include having to purchase InfiniBand server cards (which Xsigo said costs from $730 to about $860 each) and possibly new cabling for InfiniBand -- as well as the added virtualization software layer -- and workload, asset and resource tracking in virtualized environments.

"When you're looking at the big picture, yes, certainly I think there are enough benefits here that you may see this as a net cost saver," Boles said. "And I think that cost savings might be significant depending on your needs."

Blade server vendors such as Egenera Inc., Hewlett-Packard (HP) Co. and IBM also have software to virtualize network resources, but these proprietary approaches are tied to each vendor's hardware.

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