W2025 virtio NIC -> connection drop outs

[pme242]

Hi,

I have network issues with the virtio NIC on Windows Server 2025. The network connection drops for some seconds every 1-2h

PVE: 9.0.11 (fully patched)
virtio: virtio-win-0.1.285-1
VM: Windows Server 2025 (setup like suggested by Proxmox)

I've switched the vNIC to Intel E1000 - all good.

Any suggestions?

Thanks in advance.

PM

 

[_gabriel]

Test with Windows Server 2022

 

[stanthewizzard2025]

Exactly the same
Reverted to previous driver 1.271

 

[pme242]

And the revert to 1.271 fixed the issue on Server 2025?

 

[stanthewizzard2025]

YES

and for info th VM

agent: 1,fstrim_cloned_disks=1
balloon: 0
bios: ovmf
boot: order=sata1;sata0
cores: 4
cpu: host
efidisk0: SSDTHIN1:vm-401-disk-0,size=4M
machine: pc-q35-10.0+pve1
memory: 20480
meta: creation-qemu=9.2.0,ctime=1747982103
name: WS-NAS1
net0: virtio=BC:24:11:69:6A:26,bridge=vmbr0,queues=4
numa: 1
onboot: 1
ostype: win11
parent: OK
sata0: none,media=cdrom
sata1: SSDTHIN1:vm-401-disk-1,cache=writeback,discard=on,size=90G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=564d1878-18c9-8aa5-c7f0-b8e3bbccd236
sockets: 1
startup: order=2,up=1000
tags: windowsserver
tpmstate0: SSDTHIN1:vm-401-disk-2,size=4M,version=v2.0
vga: std
vmgenid: dc440efe-aed3-42e2-9f48-e577c84a447f

[OK]
#vers nvx 2.8.5
agent: 1,fstrim_cloned_disks=1
balloon: 8192
bios: ovmf
boot: order=sata1;sata0
cores: 4
cpu: host
efidisk0: SSDTHIN1:vm-401-disk-0,size=4M
machine: pc-q35-9.2+pve1,viommu=virtio
memory: 20480
meta: creation-qemu=9.2.0,ctime=1747982103
name: WS-NAS1
net0: virtio=BC:24:11:69:6A:26,bridge=vmbr0,queues=4
numa: 1
onboot: 1
ostype: win11
running-nets-host-mtu: net0=9000
runningcpu: host,hv_ipi,hv_relaxed,hv_reset,hv_runtime,hv_spinlocks=0x1fff,hv_stimer,hv_synic,hv_time,hv_vapic,hv_vpindex,+kvm_pv_eoi,+kvm_pv_unhalt
runningmachine: pc-q35-9.2+pve1
sata0: none,media=cdrom
sata1: SSDTHIN1:vm-401-disk-1,cache=writeback,discard=on,size=90G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=564d1878-18c9-8aa5-c7f0-b8e3bbccd236
snaptime: 1760896684
sockets: 1
startup: order=2,up=1000
tags: windowsserver
tpmstate0: SSDTHIN1:vm-401-disk-2,size=4M,version=v2.0
vga: std
vmgenid: 2efc3f19-939e-4fbb-97f4-dfd877ce9807
vmstate: SSDTHIN1:vm-401-state-OK

 

[_gabriel]

so title shoud be "windows virtio version 285 connection drop outs"
try without setting Multiqueue

 

[stanthewizzard2025]

need multiqueue
but could try (snapshot is my saviour)

 

[pme242]

I've reverted to 1.271, but still having some outages - less than before.
So I've switched to E1000 to fix this issue temporary.

Any idea where to report this issue?

 

[_gabriel]

have you tried without Multiqueue to dig out ?

 

[pme242]

Multiqueue isn't enabled.

 

[stanthewizzard2025]

In my case this is a ws2025 with iscsi to truenas (on the same proxmox)
No issue with network since reverting (truenas is sensible to network issues with iscsi)

 

[need2gcm]

Ran into the same issue running Windows Server 2022 on a Veeam proxy between our SAN and the backup repository with VirtIO virtual hardware used everywhere possible. Backups were failing and iscsi/disk errors were filling the System log. Tried various reconfigurations of the VM with no impact to the errors.

Upon reverting the networking drivers to 100.100.104.27100 the errors stoppe and backups began finishing as expected. I strongly suggest pulling the 0.1.285 release of the VirtIO Windows drivers from the Proxmox wiki.

 

[stanthewizzard2025]

I have 2 other windows server that don’t show the same behavior for info with 285

 

[need2gcm]

Do the servers without the errors use iscsi connections? If so, do they experience multi-gigabit load?

 

[stanthewizzard2025]

No iscsi
No multi gig load
One AD And one RDS load is very low disk network ram

 

[need2gcm]

Perhaps the error is specific to iscsi connections. Reviewing logs of another Windows 2022 VM with VirtIO on 285 but no iscsi, multi-gig traffic does not seem to experience any errors.