hardware selection for modern OSes

[CanadaGuy]

For Windows, it seems pretty straight forward: select your version, and the configuration changes accordingly.

For Linux, it seems that the base hardware of SeaBIOS, kvm64, and i440fx is selected for anything beyond kernel 2.4. However, I noticed that RHEL 9 and derivatives need the cpu set to Host for it to work.

What should drive CPU selection and hardware layer? UEFI vs SeaBIOS is pretty obvious so I don't think we need to talk much there. Before I switch my VMs over from Hyper-V to KVM/Proxmox, I'd like to have confidence that I'm choosing the right hardware layer and CPU.

Is Linux really that indifferent to the hardware that the old/basic hardware layer works just fine? Should I be selecting something other than defaults if I'm using a popular Linux OS for best performance?

Is there a matching set of choices that mimic the selection of a Generation 1 or Generation 2 VM in Hyper-V? I know BIOS vs UEFI is a big part of that.

Thanks!

 

[jdancer]

Linux is kinda indifferent in base hardware changes as long as you run "dracut -fv --regenerate-all --no-hostonly" prior to migrating to new virtualization platform.

If chosing UEFI for the firmware, then I think you need a GPT disk layout on the VM being migrated. If using BIOS as the firmware, then the VM disk layout I believe should be MBR layout.

You'll want to to use the "qemu-image convert" to convert the Hyper-V virtual disk to whatever virtual disk format you'll be using on Proxmox. Since I use Ceph, I used "raw".

 

[CanadaGuy]

Linux is kinda indifferent in base hardware changes as long as you run "dracut -fv --regenerate-all --no-hostonly" prior to migrating to new virtualization platform.

If chosing UEFI for the firmware, then I think you need a GPT disk layout on the VM being migrated. If using BIOS as the firmware, then the VM disk layout I believe should be MBR layout.

You'll want to to use the "qemu-image convert" to convert the Hyper-V virtual disk to whatever virtual disk format you'll be using on Proxmox. Since I use Ceph, I used "raw".

Thanks for the reply! What exactly does that command do? Given the context, I'm assuming it is something like "sysprep" for Windows prior to creating an image for cloning.

This is what I'm doing for the import:

qm importdisk 103 AlmaLinux.vhdx local-lvm

Don't recall where I found it, but it seems to be a higher level command supporting the import into the local-lvm destination.

**update**
dracut and selecting UEFI bios with q35 hardware and it booted perfectly! Now to test the functionality!

**update 2**
I needed to disable secure boot as well for my VM to run properly. The VM was configured in Hyper-V without Secure Boot, so I suspect that has something to do with it..

 

[jdancer]

Thanks for the reply! What exactly does that command do? Given the context, I'm assuming it is something like "sysprep" for Windows prior to creating an image for cloning.

This is what I'm doing for the import:

qm importdisk 103 AlmaLinux.vhdx local-lvm

Don't recall where I found it, but it seems to be a higher level command supporting the import into the local-lvm destination.

**update**
dracut and selecting UEFI bios with q35 hardware and it booted perfectly! Now to test the functionality!

**update 2**
I needed to disable secure boot as well for my VM to run properly. The VM was configured in Hyper-V without Secure Boot, so I suspect that has something to do with it..

Yeah, dracut is like "sysprep" for Linux.

Good deal on figuring out how to import the virtual disks.

Since all my Linux VMs are BIOS based, I don't use UEFI. Guess Proxmox enables secure boot when using UEFI.