I've recently upgraded our internet and am also upgrading our NAS to add more vdevs to the Zpool since it's getting full. However, I've noticed that all my Windows 11 VMs are experiencing terribly slow network speeds, often below 1 Mbps, while the Windows 10 VMs perform perfectly. I've done some tests including running multiple VMs together and one at a time, but I only occasionally see gigabit speeds on the Windows 11 VMs.
To troubleshoot, I checked the internet connection on an older workstation running Linux and it was fine. When testing through a 10G DAC line to the NAS, speeds were also good. The Windows 10 VMs work as expected, but the Windows 11 ones tend to lag and then occasionally burst in speed.
I even set up a fresh install of Windows 11 to rule out issues with our standard image, but I still encountered the same problem before any updates. All VMs are using storage through the NAS as netboot thin clients. Is there something I might be missing since it seems like this issue is isolated to Windows 11? Any suggestions would be greatly appreciated!
3 Answers
You mentioned your setup supports proper passthrough and has SR-IOV capability, which is great. However, if you've not updated your virtualization host or are using an outdated BIOS, it might affect how Windows 11 interacts with the hardware. You should also test if the version of Proxmox you're on has specific notes or patches related to Windows 11 performance issues. Running a fresh install is a good idea, but be sure to check every related setting to ensure everything is optimized for this newer OS.
Since you're using thin clients, the performance can sometimes choke on network I/O, particularly with multiple Windows 11 instances. Consider checking your network configuration, especially around the NAS as it could be a bottleneck. If there’s any caching that’s been implemented, it might also cause delays. Have you tried testing different protocols or adjusting the NAS settings for better VM performance?
It's likely that the network performance issues with your Windows 11 VMs could be related to the virtualization settings or the host configuration. Windows 11 VMs might require specific updates or settings that differ from Windows 10. It's essential to ensure your host operating system is fully updated and compatible with Windows 11 virtual machines. Also, check if the virtualization environment you're using is optimized for Windows 11. If the host CPU is overloaded, that could cause the slow speeds you're seeing, so monitor its usage during your tests.
Updating the BIOS and ensuring your virtualization software is compatible should help. Sometimes, even the driver versions can impact how efficiently the VMs communicate with the network.