Virtual Machine Direct Connect (VMDc) Near native performance with flexibility and data isolation
Virtual Machine Direct Connect (VMDc) enables direct networking I/O assignment to individual virtual machines (VMs). This capability improves overall networking performance and data isolation among VMs and enables live VM migration.
VMDc complies with the Single Root I/O Virtualization (SR-IOV) standard created by the PCI* Special Interest Group (PCI-SIG). Intel played a key role in defining this specification.
The latest Intel® Ethernet server controllers support SR-IOV to virtualize the physical I/O port into multiple virtual I/O ports called Virtual Functions (VFs). Each VF is then assigned to individual VMs to provide near-native networking I/O performance.
SR-IOV provides hardware-based I/O sharing
Dividing physical devices into multiple VFs allows physical I/O devices to deliver near-native I/O performance for VMs. This capability can increase the number of VMs supported per physical host, driving up server consolidation ratios to lower total cost of ownership further.
Intel’s implementation of PCI-SIG SR-IOV uses Intel® Virtualization Technology (Intel® VT) for Directed I/O (Intel® VT-d)Δ to assist the VMM in configuring direct assignment of one or more virtual functions to each VM.
Benefits of a direct I/O assignment implementation
Intel® Ethernet server controllers that support VMDc, in conjunction with support built into VM vendors’ hypervisors, can dramatically improve I/O device sharing among VMs, for higher overall performance:
- Provides near native performance due to direct connectivity to each VM via Virtual Function (VF)
- Preserves VM migration
- Increases VM scalability on a virtualized server
- Provides data protection via Intel® VT for Directed I/O
- Supports PCI-SIG SR-IOV standards
Related products and technologies
Δ Intel® VT-d enables the VMM to control how direct memory remapping (DMA) is processed by I/O devices, so that it can assign an I/O resource to a specific VM, giving unmodified guest OSs direct, exclusive access to that resource without the VMM emulating device drivers.
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