Mark Minasi's Tech Forum
Register Calendar Latest Topics Chat
 
 
 


Reply
  Author   Comment  
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #1 
I have a VHDX-file.  (Actually I don't, it's just a theoretical question.)
Can I know if that VHDX file is from a generation 1 or 2 VM ?

In article https://technet.microsoft.com/en-us/library/dn282285(v=ws.11).aspx I read :
"Can I tell whether a VHDX file was created by a generation 1 or a generation 2 virtual machine?
No. The virtual machine generation is a property of the virtual machine, not a property of the virtual hard disk."

If a VHDX for a VMgen1 can't simply be used as a VHDX for gen2, then there must be something different on the VHDX, no? So there must be a way to see if the VHDX was made for a VMgen1 or 2.

__________________
Pieter Demeulemeester
0
Wobble_Wibble

Avatar / Picture

New Friend (or an Old Friend who Built a New Account)
Registered:
Posts: 45
Reply with quote  #2 
Just speculating here, but isn't Gen2 SCSI Bott and Gen1 IDEA boot.
Therefore it's a HCL issue?


__________________
Press any key....
Yes, any key....
OK, try the space bar.
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #3 
>>Just speculating here, but isn't Gen2 SCSI boot and Gen1 IDE boot. 
Yes.

>>Therefore it's a HCL issue? 
What is HCL ? (I guess you don't mean hydrochloride)

__________________
Pieter Demeulemeester
0
wobble_wobble

Avatar / Picture

Associate Troublemaker Apprentice
Registered:
Posts: 740
Reply with quote  #4 
Hardware Compatibility List - https://technet.microsoft.com/en-us/library/cc938668.aspx
__________________
Have you tried turning it off and walking away? The next person can fix it!

New to the forum? Read this
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #5 
Still looking for a way to know if a (boot) VHDX is made for a gen 1 or a gen 2 VM.

I could make a VM gen2 and see if I can booth with the VHDX. If it does, I have my answer. But it seems a lot of work.
No way to inspect the VHDX or mount it or ... just to know the gen version ?

__________________
Pieter Demeulemeester
0
donoli

Senior Member
Registered:
Posts: 459
Reply with quote  #6 
I think that the following sites will answer all your questions.

https://technet.microsoft.com/en-us/library/dn282285(v=ws.11).aspx

https://technet.microsoft.com/en-us/library/dn282285(v=ws.11).aspx
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #7 
Hi donoli, that's the link I mentioned in the first post.
If a VM gen1 can't boot from a vhdx made with a VM gen2 and vise versa, then there must be a difference on the VHDXs, no ?
Hence my question: can I mount a vhdx and see the difference ?

__________________
Pieter Demeulemeester
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #8 
I converterd a VM gen1 to gen2 with the script mentioned in https://code.msdn.microsoft.com/windowsdesktop/Convert-VMGeneration-81ddafa2.
The VM is Win2012R2, the host is Win2012R2 with Hyper-V role.

After conversion I mounted both VHDX files on the host.

original.VHDX (gen1 VM) :
part1=350 MB (active, prim. part.)
part2=127 GB (prim. part.)
MBR

converted.VHDX (gen2 VM) :
part1=300 MB (recovery part.)
part2=100 MB (EFI system part.)
part3=127 GB (prim. part.)
GPT 

Is there a parameter that 100% garantees me that the second vhdx is a gen2 ? The EFI partition perhaps ?

__________________
Pieter Demeulemeester
0
donoli

Senior Member
Registered:
Posts: 459
Reply with quote  #9 
Quote:
Is there a parameter that 100% garantees me that the second vhdx is a gen2 ? The EFI partition perhaps ?


EFI could be the answer.  Some months ago, I asked a question about EFI in relation to booting non windows VMs.  Mark answered based on some new research that he did on EFI.  I haven't seen any posts by him lately. Maybe he is just enjoying the Florida sun. 
0
Wes

Senior Member
Registered:
Posts: 189
Reply with quote  #10 
The difference is GPT vs MBR (and by extension, on the VM itself, UEFI vs BIOS).

If you want to know if you have a GPT or MBR vhdx, you can simply mount it and pop into disk mgmt and right click on it to see if you get the option to convert to GPT or convert to MBR (then you know which one you'd be converting *from*)!

And yes seeing an EFI partition will also be a tipoff that you'd need to run this in a gen2 VM.
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #11 
Hi Wes, does that mean that GPT is only possible on a VM gen2 and that MBR is only possible on a VM gen 1 ?

BTW: no need to initiate a conversion GPT-MBR in Disk Mgmt. In the properties of the disk, on tab 'Volumes' you see the Partition style: MBR or GPT.

For me, the question is whether MBR and GPT are unambiguous indications that the VM is gen 1 or 2.


__________________
Pieter Demeulemeester
0
Wes

Senior Member
Registered:
Posts: 189
Reply with quote  #12 
A uefi machine - like a gen2 vm - boot volume has to be gpt. I can't speak to whether or not a Linux gen1 vm could use gpt or not but a windows gen1 boot volume would be using mbr. Data volumes could be anything.
0
Pieter

Avatar / Picture

Senior Member
Registered:
Posts: 130
Reply with quote  #13 
OK, thanks Wes. That answers my question.



__________________
Pieter Demeulemeester
0
Previous Topic | Next Topic
Print
Reply

Quick Navigation: