This article can also be found in the Premium Editorial Download "Storage magazine: 2009 Storage Products of the Year."
Download it now to read this article plus other related content.
Current I/O virtualization products
The general IOV approach that most current products take is to connect the local host servers into a top-of-rack unit that holds a variety of network, storage and graphics adapters that can act as a dynamic pool of I/O connectivity resources. The top-of-rack device acts as an I/O fabric for the servers in the rack, and can communicate with other servers in the rack or can connect to end-of-row switches for more distant resources. These IOV top-of-rack units may be less expensive than some of the newer high-speed top-of-rack switches.
Click here to view a PDF of the I/O virtualization product sampler.
Two specific implementation models for I/O virtualization are emerging: PCIe- and InfiniBand-based approaches.
One approach to IOV is to extend the PCI Express bus out of the server chassis and into a separate box or chassis populated with IOV-capable adapters that can be shared across multiple servers. The I/O virtualization box would be installed in a rack and would function somewhat similarly to a top-of-rack switch, except that instead of only supporting Ethernet or Fibre Channel, this IOV box would act as a type of fabric switch for all LAN, SAN, DAS and possibly graphics traffic. At least three companies are working on products that extend the PCI Express bus into a separate box for the purpose of virtualizing I/O adapters. One advantage to this approach is that servers today already support PCI Express. Some IOV vendors now have first-generation products available and some are publicly discussing products that will appear this year. Some of these products require support for SR-IOV or Multi-Root IOV (MR-IOV), but others don't have that requirement. These products are built around the PCI Express 2.0 specifications, and vendors already have PCI Express 3.0 plans in their product roadmaps.
Aprius Inc. is a small vendor that's building a PCI Express gateway device that will support almost any type of PCI Express adapter (including network cards, storage controllers and graphics coprocessors) that can then be shared across multiple servers. These adapters basically form an I/O resource pool that can be dynamically assigned to physical or virtual servers.
NextIO is a company that was involved with developing the PCI-SIG I/O virtualization specifications and had some IOV products as early as 2005. NextIO is working in several areas, including the high-performance computing (HPC) market and is interested in virtualizing graphics coprocessing in addition to traditional networking and storage I/O traffic. They're partnering with several big name vendors for a variety of IOV applications.
VirtenSys Inc. extends the PCIe bus with its I/O virtualization switches that can virtualize the major types of server networking and storage connectivity, as well as interprocessor communication (IPC) for HPC compute cluster environments.
This was first published in February 2010