Date Published	June 2026
Affected Product	Versa VOS on Microsoft Azure
Severity	High — potential 50%+ throughput degradation
Status	Interim mitigation available; full support in a future VOS release

⚠ WARNING: Customers running VOS on Azure VMs that have been stop-deallocated and restarted or redeployed may be migrated to MANA-capable hardware. Until native MANA support is released, opt-out of MANA NIC eligibility is required to maintain performance.

Overview

Microsoft is rolling out the new Microsoft Azure Network Adapter (MANA) hardware across existing Azure VM size families. For more information on MANA, refer to the Microsoft documentation:

Azure Accelerated Networking — MANA for Existing Sizes

While MANA is designed to enhance performance for modern workloads, Versa VOS is not yet fully optimized for this hardware. The MANA NIC driver requires a minimum kernel version of 6.2 and stable DPDK 24.11 support. Support for MANA in VOS on Ubuntu Jammy (kernel 6.8) is planned for a future release.

The Issue

On VOS releases prior to full MANA support, if a VOS instance is paired with a MANA NIC, the dataplane will attempt to fall back to the synthetic interface path rather than using the high-performance DPDK driver. This condition can occur on any Azure VM that is stop-deallocated and restarted or redeployed onto MANA-capable hardware.

⚠ WARNING: This fallback can result in a 50% or greater reduction in maximum throughput, significantly impacting the performance of your SD-WAN or security infrastructure.

Affected Configurations

Dimension	Details
Platform	Microsoft Azure VM-hosted VOS instances
VOS Versions	All versions prior to full MANA support (see release notes for the specific version when published)
Trigger	VM stop-deallocated and restarted, or redeployed onto MANA-capable hardware
Indicator	Presence of a MANA Virtual Function in the guest OS network interface list

ℹ NOTE: To check whether your VM has been migrated to MANA-capable hardware, inspect the guest OS network interfaces. The presence of a MANA Virtual Function indicates the VM is running on MANA hardware.

Required Action — Opt Out of MANA NIC Eligibility

To maintain current performance levels and prevent automatic pairing with MANA NICs on stop-deallocated and restarted or redeployed VMs, customers must opt out of MANA NIC eligibility for their affected Azure instances.

Please refer to the following Microsoft documentation for opt-out instructions:

Azure Network Virtual Appliance MANA Opt-Out FAQ

Summary of Steps

The Microsoft documentation above provides the complete opt-out procedure. At a high level:

Identify Azure VMs running VOS that have been or may be stop-deallocated and restarted or redeployed.
Apply the MANA opt-out tag or configuration to those VM instances as described in the Microsoft FAQ.
Verify the opt-out is in effect before the next maintenance window or restart.
Contact Versa support if you observe performance degradation consistent with synthetic interface fallback.

Long-Term Resolution

Versa Networks is actively working to add native MANA NIC support to VOS. The following conditions must be met for full MANA support:

Minimum kernel version: 6.2 (Ubuntu Jammy ships with kernel 6.8, which satisfies this requirement)
DPDK version: 24.11 or later (stable MANA driver support)

When native MANA support is available, customers will be able to take full advantage of MANA hardware and Azure Boost performance benefits without degradation or the need to opt out.

ℹ NOTE: Versa will publish a separate release advisory when MANA support is generally available in VOS. Customers are encouraged to monitor the Versa release notes and this knowledge base for updates.

Technical Assistance

If you are experiencing performance degradation on Azure VOS instances or need assistance verifying whether your deployment is affected, please open a case with Versa Support:

Email: support@versa-networks.com

Please include the following information in your case:

VOS version currently running
Azure VM size and region
Whether the VM has been stop-deallocated and restarted or redeployed recently
Output of network interface listing from the guest OS