linux VMs using virtio_net lose network connectivity

[volker]

Hi everybody,

I have several occurrences of Linux VMs losing connectivity on the virtio_net device.

If it happens, no traffic goes over the virtio_net network interface. Unloading and reloading the virtio_net kernel module in the VM does fix the problem as well as rebooting the VM.

Proxmox 3.4.11 and several types of VMs: suse 12.2, 13.1, centos 6.7

Regards
....Volker

 

[manu]

Hi, do you think anything in /var/log/syslog related to the problem ?
Is the link detected as active with ethtool ?

 

[volker]

Hi. Just happend again.
There is nothing noticeable in the logs of the VM. However I can deduce the time when the VM lost connectivity from errors that the nfs server became unreachable.
And there is nothing noticeable in the logs of the host as well at that point in time.

ethtool says link connected on the VM

tcpdump on the VM still shows some other traffic, mostly ARP, but also some UDP and ICMP packets. Pings directed to or originating from the VM don't show up however.

Unloading and reloading the module on the VM fixed the problem.

Regards
....Volker

 

[manu]

Are you using the 3.10 kernel on the host ? If not I advise you to upgrade to it.