Single Root I/O Virtualization

Single Root I/O Virtualization (SR-IOV) is an extension to the PCI Express (PCIe) specification that improves the performance of virtual networks for OpenStack workloads. SR-IOV enables network traffic to bypass the level of software switching and interact directly with PCI network device resources within a virtual machine.

By using SR-IOV, you can achieve network performance levels nearly equal to non-virtualized hardware. SR-IOV allows multiple virtual machines to share a single physical network interface, known as a Physical Function (PF), by creating child network interfaces called Virtual Functions (VFs).

SR-IOV use cases

Mirantis validates the following common SR-IOV usage scenarios to ensure architectural stability and high-performance networking:

  • North-South routing with distributed floating IP addresses

  • North-South routing with non-distributed floating IP addresses

  • Tenant network connectivity

These use cases have different limitations depending on the networking backend. Use the following table to verify compatibility for your deployment.

SR-IOV compatibility by connectivity

Type of connectivity

Open vSwitch (OVS)

Open Virtual Network (OVN)

Tenant network non-SR-IOV port and SR-IOV port (different compute nodes)

Tenant network non-SR-IOV port and SR-IOV port (same compute node)

North-South routing (distributed floating IP address)

North-South routing (non-distributed floating IP address)

See also