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Add VHDX support

Posted: 27. Jul 2017, 17:59
by RubensRainelli
Since VHDX are really more powerful, and are lesser corruptible on unattended current interruption.

I use often VHDX on my PC for dual boot VHDX based OSes.

I remember that VHDX are compatible in Windows since 8.0 and guestable with a Microsoft patch on Windows 7 (don't remember wich KB)

Re: Add VHDX support

Posted: 27. Jul 2017, 18:10
by socratis
VHDX is supported readonly only so far. You need to convert it to a format which VirtualBox supports writing to like VDI, VHD or VMDK in order to attach it to a VM. This can be done using VBoxManage in the Command Prompt:
  • VBoxManage clonemedium disk <inputVHDX> <outputDisk> --format --format VDI|VMDK|VHD

Re: Add VHDX support

Posted: 27. Jul 2017, 19:10
by RubensRainelli
socratis wrote:VHDX is supported readonly only so far. You need to convert it.
Doing this I would loose advantage of VHDX and would not be a good one.

Re: Add VHDX support

Posted: 27. Jul 2017, 19:21
by socratis
You could always contribute the source code. ;)
I don't think that it's high in the priorities of the developers, mainly because not that many people ask for it and primarily paying customers don't really ask for it. But, you never know...

Re: Add VHDX support

Posted: 28. Jul 2017, 09:25
by mpack
RubensRainelli wrote:Since VHDX are really more powerful, and are lesser corruptible on unattended current interruption.
No more so than VDI, VirtualBox's native format. Why not just use VDI? Can you be specific about the advantages of VHDX that you find attractive?

Re: Add VHDX support

Posted: 28. Jul 2017, 18:58
by RubensRainelli
socratis wrote: paying customers don't really ask for it.
The competitors, obviously except Microsoft, doesn't support it. This would be a big win ;)
mpack wrote:Can you be specific about the advantages of VHDX that you find attractive?
First of all: ability to native boot VHD and VHDX, so Virtual could become also "phisical" to have full power in some situations;
- VHDX support 64 TB disks (VHD 2 TB);
- VHDX are more performance than VHD since support 4kb logical sector;
- VHDX support anti corruption while you encounter an unattended shutdown (critical need for safety).
- support bigger cluster;
- support trimming;
- support cluster metadata;
- other stuff I don't remember right now.

Key benefits are primarily for Enterprise customers :)

Re: Add VHDX support

Posted: 28. Jul 2017, 19:02
by scottgus1
RubensRainelli wrote:native boot VHD and VHDX, so Virtual could become also "phisical"
When you toggle-boot an OS in Virtualbox and on the physical motherboard, the hardware presented to the guest OS will change. Maybe MS's Hyper-V can handle this, but Virtualbox will give a complete new hardware list to the guet, except for the CPU itself. The gust OS will have to compensate if it can, and reactivation may be required.

Re: Add VHDX support

Posted: 29. Jul 2017, 09:10
by mpack
RubensRainelli wrote: - VHDX support 64 TB disks (VHD 2 TB);
The part about VHD only supporting 2TB is false. Ditto if you had said the same about VDI. The VHD header and footer both use 64bit fields to describe element sizes. This 2TB myth probably came from the fact that 2TB is the maximum size disk that can be handled by a legacy BIOS (e.g. like an XP VM uses). So an "XP Mode" VM would have been limited to 2TB disks, but because it was MBR and XP, not because it used VHD format.

Re: Add VHDX support

Posted: 31. Jul 2017, 11:00
by RubensRainelli
mpack wrote:This 2TB myth probably came from the fact that 2TB is the maximum size disk that can be handled by a legacy BIOS
It's Microsoft to tell, not a myth :/

Microsoft Technet: VHD vs VHDX
https://blogs.technet.microsoft.com/aus ... h-hyper-v/

Re: Add VHDX support

Posted: 31. Jul 2017, 16:48
by mpack
I have personal experience of implementing a VHD parser, so I have no need to rely on hearsay. And I re-checked my sources before making my previous post. I am correct.

Re: Add VHDX support

Posted: 31. Jul 2017, 17:01
by RubensRainelli
Good to know, anyway I assure that VHDX are more fail safe and faster. This is imperative for business uses, I think.

Re: Add VHDX support

Posted: 31. Jul 2017, 17:38
by socratis
RubensRainelli wrote:This is imperative for business uses, I think.
That's part of the misconception of the whole situation I believe. The fact that "you think". The people that "know" however have not deemed it necessary to add VHDX support. I believe that VDI is more than enough for their business needs. And more...

Re: Add VHDX support

Posted: 31. Jul 2017, 19:08
by RubensRainelli
socratis wrote:The people that "know" however have not deemed it necessary to add VHDX support. I believe that VDI is more than enough for their business needs.
On some PC I had problems with networks enabling Hyper-V, so for this I'd love to been able to use VirtualBox for VHDX. Since I had broken VMs from unreadable vDisks. Since using VHDX problem has expired.
And about performance... huge difference.

Re: Add VHDX support

Posted: 31. Jul 2017, 19:59
by Martin
Nobody here is discussion advantages of VHDX versus VHD.
Virtualbox prefered format is VDI, not VHD ;)

Re: Add VHDX support

Posted: 31. Jul 2017, 20:16
by scottgus1
Actually, Ruben, most of us wouldn't be able to add VHDX support to Virtualbox even if we totally agreed with you and felt VHDX needed to be in Virtualbox super-pronto. The developers and Oracle make those decisions. We're just users like you. You'd have to convince the developers and Oracle exec's. And you'd need some cha-ching to do so.

Oracle's development on free Virtualbox comes from developments on Oracle's pay-for virtualization system which is derived from Virtualbox. The license to begin getting developer support on pay-for Virtualbox starts at $6100 (that's $61 per license, 100 license minimum). The developers have said they have their hands over-full handling Oracle's customers' development needs, so we should not expect enhancements suggested by free users to be high on the list unless the enhancements coincide with rich paying customers' needs. That said, users can contribute code, and free Virtualbox is open-source, so someone could figure out how to implement what they'd like Virtualbox to have and submit a code suggestion.