Are vdisks on the same OS interchangeable between VMs?

[crazykidguy]

I recently upgraded my system from Intel to Ryzen and didn't save the XML for my Win10 VM but I still have its vdisk. I fired up a different VM with a different machine type (i440fx to Q35) and CPU cores (increased cores) and pointed the primary vdisk to the old disk location but I couldn't get it to boot. I tried decreasing the core count and no GPU passthrough to try to make sure it's nothing funny with the GPU. 

 

Is it not possible to boot an old vdisk with different VM settings as the original VM? 

Once you've created a VM, are you not able to change its machine type and add/remove cores with the same vdisk? I tried doing this with a new VM and it would not boot after I changed the machine type. 

[david279]

yes you can just setup a vm in the template and point it to your old vdisk. it should work.

[testdasi]

8 hours ago, crazykidguy said:

I recently upgraded my system from Intel to Ryzen and didn't save the XML for my Win10 VM but I still have its vdisk. I fired up a different VM with a different machine type (i440fx to Q35) and CPU cores (increased cores) and pointed the primary vdisk to the old disk location but I couldn't get it to boot. I tried decreasing the core count and no GPU passthrough to try to make sure it's nothing funny with the GPU. 

 

Is it not possible to boot an old vdisk with different VM settings as the original VM? 

Once you've created a VM, are you not able to change its machine type and add/remove cores with the same vdisk? I tried doing this with a new VM and it would not boot after I changed the machine type. 

You need to clarify what you meant by "couldn't get it to boot". It's ambiguous.

Does the VM errors out when you click Start? Does it show the Tianocore screen but get stuck there? Does it boot into a command line interface? Does it get in a boot loop?

 

You can change machine type with no issue (but you have to create a new template - the GUI can't handle changing machine type on an existing template).

The exception to that is if you were on SeaBIOS (default for typical guide with i440fx) and switching to OVMF (required for Q35). From my experience, that won't work out of the box.

 

Also make sure your vdisk settings is of the right format (check your xml), especially if you were using qcow2 in the old template.

[crazykidguy]

12 hours ago, testdasi said:

You need to clarify what you meant by "couldn't get it to boot". It's ambiguous.

Does the VM errors out when you click Start? Does it show the Tianocore screen but get stuck there? Does it boot into a command line interface? Does it get in a boot loop?

 

You can change machine type with no issue (but you have to create a new template - the GUI can't handle changing machine type on an existing template).

The exception to that is if you were on SeaBIOS (default for typical guide with i440fx) and switching to OVMF (required for Q35). From my experience, that won't work out of the box.

 

Also make sure your vdisk settings is of the right format (check your xml), especially if you were using qcow2 in the old template.

Sorry, I should've clarified. I've set up 2 VM templates with Q35 and i440fx machine types to test the vdisk. No pass-throughs, VNC only, 4cores/8threads, Ryzen 2700x. 

 

On the Q35 machine, the VM gets to the TianoCore load screen and then kicks me into the standard Win10 recovery menu. I try hitting the Diagnose option and it will go to the screen where it runs the disk check but eventually I will get an error that the disk check failed. I then tried loading the driver based on this thread but it didn't work either:

 

 

If I ignore it and tell the machine to restart anyway, it will go back to the TianoCore screen and spin until it freezes. 

 

On i440fx, the VM doesn't get pass the TianoCore screen and continues to do the load up spinning animation. 

 

I've let both tests spin for over 4 hours and nothing ever comes up. 

[bastl]

Switching the machine types if the the BIOS version is setup the same should work fine. Switching from OVMF to seabios or reverse won't work at all. A UEFI windows install isn't bootable in a none UEFI environment. Windows itself can't fix it. There are workarounds for this, but it's a pain in the butt.

[testdasi]

8 hours ago, crazykidguy said:

Sorry, I should've clarified. I've set up 2 VM templates with Q35 and i440fx machine types to test the vdisk. No pass-throughs, VNC only, 4cores/8threads, Ryzen 2700x. 

 

On the Q35 machine, the VM gets to the TianoCore load screen and then kicks me into the standard Win10 recovery menu. I try hitting the Diagnose option and it will go to the screen where it runs the disk check but eventually I will get an error that the disk check failed. I then tried loading the driver based on this thread but it didn't work either:

 

On i440fx, the VM doesn't get pass the TianoCore screen and continues to do the load up spinning animation. 

 

I've let both tests spin for over 4 hours and nothing ever comes up. 

Please attach the xml of your 2 VM's.

If copy-paste, please use the forum code functionality (the </> button next to the smiley button) separately for each xml (i.e. split them out).