Microsoft’s networking team has changed the way network interface cards (NICs) are certified for use in Windows Server.
As team member Dan Cuomo explained, since the days of Windows Server 2008, Microsoft has certified network adapters “based on adapter link speed, which means that any 10Gb adapter /s or higher had additional requirements (Microsoft testing) placed on it, regardless of the intended use of the adapter (as designed by the manufacturer).
This approach meant that some network card vendors would test speed, not actual performance. Yet servers are now being asked to do all sorts of I/O-intensive tasks, like driving Microsoft’s Storage Spaces Direct software-defined storage product, which is increasingly used in hyperconverged infrastructures.
Raw speed isn’t an indicator of how well a network card is working on a server that’s essentially being asked to act as a shared storage array, according to Microsoft. Microsoft’s old certifications therefore left customers unaware of the scenarios a network card might struggle to handle.
Microsoft realized that its approach of assuming that a faster network adapter is a better network adapter was inappropriate after the launch of Windows Server 2022.
Cuomo said the arrival of the operating system has seen “an increasing number of support cases which have resulted in the frustrating ‘unsupported’ support request despite the device being certified”.
Microsoft’s answer is a NIC certification scheme that rates performance based on a device’s ability to perform in three roles:
- Calculation traffic: Traffic originating from or destined for a virtual machine (VM).
- Storage traffic: Traffic using Server Message Block (SMB), for example, Storage Spaces Direct or SMB-based live migration.
- Management traffic: Traffic to or from outside the local cluster. For example, Storage Replica traffic or traffic used by the administrator for cluster management such as Remote Desktop, Windows Admin Center, Active Directory, etc.
The new certification scheme does not associate network adapters with Microsoft products or applications.
“This change is intended to end the perilous phrase ‘I’m sorry, but your configuration is not supported,'” Cuomo wrote. “We’ve heard your comments about the frustration of calling support with a certified device only to find out that the adapter can’t be supported the way you’re using it.”
Not all network adapters will be certified to meet any of Microsoft’s roles. In this case, Cuomo said it might still be acceptable to support an app that has a different traffic profile. ®
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