I/O virtualization (IOV)

I/O virtualization (input/output virtualization or IOV) is the abstraction of upper layer protocols from physical connections or physical transport.

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 input/output (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.

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. The Single Root (SR-IOV) standard specifies how multiple guests on a single server with a single PCI Express (PCIe) controller or root can share I/O devices without requiring a hypervisor on the main data path. Multiple Root IOV (MR-IOV) extends the concept to allow multiple independent systems with separate PCIe roots to connect to I/O devices through a switch. Both SR-IOV and MR-IOV require specific support from I/O cards.

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.

See also: converged network adaptor (CNA), Fibre Channel over Ethernet (FCoE)

This was last updated in April 2011

Continue Reading About I/O virtualization (IOV)



Find more PRO+ content and other member only offers, here.

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.


File Extensions and File Formats

Powered by: