XCP-NG: Low Download Speeds on W10 VM

Hey, anyone else having issues with W10 VMs lately?

I can’t seem to diagnose the issue. It used to work fine before, now I’m getting less than 1Mbps download speeds, while the upload speeds match the one provided by my ISP.

SMB shares take an infinitely long time to access, though I can’t interact with the files because the connection is too slow. Any ideas what could be happening here?

I just spun up a new VM and it’s the same issue. Could it be something with the XCP-NG Windows VM network drivers?

All of our are working fine, not aware of any changes to XCP-NG that would cause that, more likely some networking issues.

Yeah, that seems to be the case.

Switched the VM to the management VLAN and now everything is smooth, though no other VMs on the previous VLAN have such issues, so that doesn’t make much sense either.

Further information, this seems to occur on all 2.5G VLAN networks, with the UTP going directly into the NG4100.

Quite strange since none of my other Linux VMs in those 2.5G VLAN networks seem to be affected. Any way to diagnose if this is a cable issue, via the cli?

… Swapped the cable, same results

iperf3 results show a ~1.5Gb bitrate between the 2.5G linux hosts, so it doesn’t seem like the firewall is making the problem. All of this smells like some networking driver bug for windows VMs, or some network missmatch (since management works fine, which is 1G, separate port). Also windows shows that the connection speed is 1G even when the 2.5G adapter is set for that VM in xoa.

Have you tried creating another VIF and deleting the one which the VM had during its initial creation. There is an issue with Windows Server 2019 about losing connectivity when doing Samba Share that was discussed in XCP-NG forums. I was thinking it is the same scenario:

Windows Server 2019 Guest loses Network Connectivity | XCP-ng and XO forum

Yeah, I created a whole new VM, same result.

Further tests show that this occurs on all 2.5G VLAN networks, on all of my XCP hosts, only on windows VMs, Completely unsure as to why.