multiple VMs go to 100% CPU on one vCPU per VM

[sstillwell]

This has just recently started occurring. Sometime overnight (possibly after Proxmox Backup Server job? Unsure) many of my VMs will have one vCPU go to 100% (a single core VM will show 100%, a dual-core VM will show 50%, four cores shows 25%, etc.). The overall host utilization will go up to around 45-55%.

These VMs don't have a lot in common - they're a mix of Windows, Linux, and FreeBSD guest OSes. If I shut the VMs down and restart them, all will be normal until the next night, when the process repeats.

The only VMs that this seems to not affect is the VM running Proxmox Backup Server, and another single-core VM running an old 32-bit instance of Windows 2003 Server.

All of the VM guest OSes are patched current, or at least within the last week.

This behavior just started within the last week. Proxmox VE is at 8.1.3 and patched current on the pve-no-subscription repository. Host machine is a Supermicro Xeon-D 1541 with 128 GB of RAM, VM storage on NFS share (Synology NAS) over 10Gbit link

 

[leesteken]

Sometime overnight (possibly after Proxmox Backup Server job? Unsure) many of my VMs will have one vCPU go to 100% (a single core VM will show 100%, a dual-core VM will show 50%, four cores shows 25%, etc.). The overall host utilization will go up to around 45-55%.

Maybe it's this: https://forum.proxmox.com/threads/p...e-vms-are-idle-at-0-5-cpu.138140/#post-616210

 

[sstillwell]

Yeah, quite possible. The only way I noticed it initially was that the host CPU fans would spin up from load and I would wonder why it was so loud...

It sounds like there's a workaround - I'll give that a try.

EDIT: Downgraded pve-qemu-kvm from 8.1.2-5 to 8.1.2-4 and rebooted the host. We'll see if that resolves the issue tonight. Given everyone else's experience, I expect that it should.