Migrating SeaBIOS VMs from Legacy Proxmox node to UEFI Proxmox node – any issues?

[feliceM]

I have an existing Proxmox 9.x node installed in Legacy BIOS mode.
The VMs on this node were created with SeaBIOS and are currently running fine.

I am preparing a second server where Proxmox 9.x has been installed in UEFI mode.

I would like to migrate the existing VMs (offline migration is fine) from the legacy-installed node to the UEFI-installed node.

My question is:

Will the difference in host boot mode (Legacy vs UEFI) cause any issues for the migrated VMs, assuming the VMs themselves remain configured with SeaBIOS?

In other words:

• Is host boot mode independent from guest firmware in Proxmox/QEMU?
• Or does a destination host installed in UEFI mode require VM conversion to OVMF / UEFI to boot correctly?

I’m specifically interested in real-world experience with mixed host boot modes.

 

[cheiss]

Is host boot mode independent from guest firmware in Proxmox/QEMU?

Yes. It does not matter for VMs how the host boots (one of the advantages of virtualization in fact, that guests are independent of the actual hardware of the host!)

 

[Impact]

The only thing I can think of that would be affected is if you do passthrough which from what I've seen sometimes behaves a bit differently. Secure Boot can apparently also have an effect.