The IT Cave

What Is the Proxmox VM Machine Version?

Despite how it might sound, the Machine setting isn’t the version of your operating system or even really the “version” of your VM. Proxmox VE uses QEMU/KVM to provide virtual machines. The machine type defines the virtual motherboard and hardware layout presented to the guest operating system. You’ll generally encounter two families of machine types: i440fx — the older, very widely compatible virtual chipset.

Why Would You Upgrade the Machine Version?

There isn’t usually a reason to update every VM simply because a newer machine version appears in the dropdown. In fact, if the VM works perfectly and Proxmox isn’t warning you about its machine version, leaving it alone is often perfectly reasonable. There are several circumstances where upgrading makes sense, though. 1.

When Should You NOT Upgrade It?

There are also some good reasons not to immediately change the setting. The most obvious is: The VM works, its machine version is supported, and you don’t need anything provided by a newer version. There is little benefit in introducing a virtual hardware change just for the sake of having the highest number in the dropdown. You should also be cautious with VMs running software that is sensitive to hardware changes.

What About a Proxmox Cluster?

Clusters add another consideration. Don’t update a VM to a machine version that some of your nodes cannot support if you expect that VM to migrate or fail over to those nodes.

Can You Go Back?

This is why writing down the old version and taking a backup matters. If the new machine version causes problems, shut the VM down and change the Machine setting back to its previous version. For example, if you changed: pc-q35-8.1 to: pc-q35-10.0 and the VM behaves strangely, shut it back down and restore the previous machine version. That said, don’t rely on rollback as a substitute for a backup.