VM randomly freezes

[pos-sudo]

Hello,

We've running several VM's on a Proxmox 8.0.3 node. We used USB devices on the VM hardware and passhrough to an external HDD for backups. since several days 2 VMs (not at the same day) didn't response to ping and actually 'freezes' because Proxmox said that the VM is running but cant type anything in the VNC on the specific VM. Actually after Stop/Start the VM runs as usual again. Since this is the second time it happens with two different VMs on the same node I was wondering what it could be and how to mitigate the possible issue.

I checked already the journalctl, kern and crash logs in the VM but can't find anything that is related to this issue. Also on the Proxmox VE syslog nothing I can see which is possibly causing this. the VMs came from an other node with a different CPU but that was month's ago and I've kvm64 virtualisation enabled. Both servers run PLESK but no backups are running when this issue occurs.

Thanks in advanced for the help!

 

[Moayad]

Hello,

I would also check the resources used before the VM got freeze, if the issue happened again I would "temporarily" disconnecting the USB devices to see if the issue persists.

 

[pos-sudo]

Hello,

I would also check the resources used before the VM got freeze, if the issue happened again I would "temporarily" disconnecting the USB devices to see if the issue persists.

Thank you for the quick response. Resources are OK only proxmox says the RAM is full but it is cached in the VM itself. Also I was wondering if it is possible to prevent the external HDD from being into sleep mode? If that is the problem?

 

[pos-sudo]

Dear,

It happend again today but with a complete other VM. Also here we saw that when the VM 'freeze' the CPU is 100% constantly. In the VM there are logs that are saying input/output error of the attached virtual HDD as USB device. I have decided to remove the USB drive from the VM. Do you think that this prevents this issue from occurring again?

Thanks in advance for the help!