Accelerated Networking with Azure virtual machine disaster recovery

Accelerated Networking enables single root I/O virtualization (SR-IOV) to a VM, greatly improving its networking performance. This high-performance path bypasses the host from the datapath, reducing latency, jitter, and CPU utilization, for use with the most demanding network workloads on supported VM types. The following picture shows communication between two VMs with and without accelerated networking:

Screenshot of difference between accelerated and nonaccelerated networking.

Azure Site Recovery enables you to use the benefits of Accelerated Networking for Azure virtual machines that you fail over to a different Azure region. This article describes how you can enable Accelerated Networking for Azure virtual machines replicated with Azure Site Recovery.

Prerequisites

Before you begin, make sure you understand:

Support requirements

Site Recovery preserves Accelerated Networking only when it is enabled on the source NIC and the exact recovery VM size, image, operating system, region, and NIC configuration support it. Validate the recovery configuration by capability rather than relying on a static VM-family or operating-system list.

Some NC and NV sizes can appear in capability-query results even though they don't support Accelerated Networking. Confirm support for the exact target size before failover. For maintained requirements and capability checks, see Accelerated Networking limitations and constraints.

If the source VM doesn't have Accelerated Networking enabled, enable it before expecting Site Recovery to preserve it.

Enabling Accelerated Networking for replicated VMs

When you enable replication for Azure virtual machines, Site Recovery automatically detects whether the virtual machine network interfaces have Accelerated Networking enabled. If Accelerated Networking is already enabled, Site Recovery automatically configures Accelerated Networking on the network interfaces of the replicated virtual machine.

You can verify the status of Accelerated Networking under the respective NIC's tab in the Network settings for the replicated virtual machine.

Screenshot of Accelerated Networking setting.

If you enable Accelerated Networking on the source virtual machine after enabling replication, you can enable Accelerated Networking for the replicated virtual machine's network interfaces by the following process:

  1. Open Network settings for the replicated virtual machine.
  2. Select the name of the network interface under the Network interfaces section.
  3. Select Enabled from the dropdown for Accelerated Networking under the Target column.

Screenshot of Enable Accelerated Networking.

Follow the preceding process for existing replicated virtual machines that didn't previously have Accelerated Networking enabled automatically by Site Recovery.

Next steps

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