Virtual network adapter types

Most hypervisors offer the following methods for defining network adapters for a virtual machine guest operating system: emulated and paravirtualized/synthetic.

Emulated

With an emulated network adapter, a hypervisor presents the definition of a legacy, real-world, PCI-based, network interface to the operating system of a guest virtual machine.Emulating an older network adapter, such as a basic 1Gb Intel NIC 82545E, helps ensure that the operating system has native device drivers that are compatible.Emulated network adapters work in nearly all situations and require no additional software.

Because a device driver is required for the emulated network adapter, the operating system of the guest virtual machine uses more CPU resources to process all network traffic.On a host with multiple guest virtual machines, those CPU resources are consumed more extensively.

It is important for you to understand that emulated virtual network adapters result in higher CPU resource utilization than network adapter drivers on a non-virtualized installation.For some PureConnect products that use significant CPU resources in normal operation, this increase in CPU utilization can result in errors and issues as CPU resources are consumed and exhausted.

Paravirtualized (VMWare)/Synthetic (Microsoft Hyper-V)

Paravirtualized or synthetic network adapters are a more-recent network solution for virtualization.For paravirtualized/synthetic network adapters, the hypervisor presents an abstraction of a network adapter as a generic PCI device to the operating system of the guest operating system.

The hypervisor provides software for installation on the operating system of the guest virtual machine.The software enables the operating system to use the abstraction as a network interface.

Generally, paravirtualized/synthetic network adapters are presented by the hypervisor to the operating system of the guest virtual machine as a 10Gb network interface.Because there is no specific device driver, the operating system of the guest virtual machine uses fewer CPU resources to process network traffic.

Recommendation

In general, we recommend that you use paravirtualized/synthetic virtual network adapters in virtual environments for PureConnect and its subsystems.