Booting a Windows VM from Real physical disc or a physical EXT USB

Hi folks
Not sure if this works on HYPER-V but using KVM/QEMU you can boot a Windows VM from a real physical HDD or a Windows to Go stored on an external USB.

This means that you can say backup an image of your REAL Windows system and then attach the disk to the VM and then set it as the boot device

Most of the drivers should be fine !!! and you should be able to get as near native speed as makes no difference -- the main problem I'd imagine for users here is the graphics as a lot here won't have a spare graphics port (separate graphics outlet - not simply "dual monitor support" from one card). However you can still paravirtualize the graphics -- you'll need to install the appropriate graphics driver -- the one to use is from the REDHAT / FEDORA Win virtio iso --works on other distros such as ubuntu / debian / arch linux etc.

Those without dual NIC's can also share the single NIC for networking.

Cheers
jimbo

I'd like to tell you about Disk2vhd. It's a lightweight tool that you run on your host-machine. It creates a vhd/vhdx-file which will be a complete copy of your host-machine. You can then send this vhd/vhdx-file anywhere and use it to boot VMs with.

hajen said:

I'd like to tell you about Disk2vhd. It's a lightweight tool that you run on your host-machine. It creates a vhd/vhdx-file which will be a complete copy of your host-machine. You can then send this vhd/vhdx-file anywhere and use it to boot VMs with.

Hi there
another OK solution - but using any sort of "Non native" file system / I/O will decrease the performance of the VM -- the idea is to get the VM to perform as near possible to Native speed -- having VHD/VHDX files means that essentially the I/O algorithms take longer to execute because you have to map the vhd/vhdx structure to the OS underlying file system .

Assuming enough RAM in the system the biggest bottleneck to Virtual Machines is within the Disk I/O subsystem -- actually most consumer grade computers suffer from poorish Disks as well !!

Commercial servers Virtualize cloud and other servers by using things like SAS- Fibre etc for extremely fast I/O -- for a lot of servers --themselves running as Virtual machines - graphics isn't an issue as that can be done on the remote clients.

At a consumer level Disks are still the most important part -- get those right and the rest will usually follow. __Most CPU's on home computers these days are perfectly capable of running certainly up to 3 VM's concurrently - depending on your RAM availbility they could run more.

Remotely accessing the VM (even on a LAN) with a machine with good graphics will yield an even better performance --assuming your LAN is nice and fast --Graphics in my laptop is far superior to that on the HOST SERVER and so I use krdc to access the Windows VM on my main server.

Cheers
jimbo

kvm-qemu lets you get crazy with block devices. You can for example boot a windows machine to linux. Make a tmpfs ramdisk. Make a qcow write layer in the ramdisk with the physical machine hd as base. Mount that to qemu-nbd service. And on another machine, boot the remote machines hard drive. This would leave no trace on the host system that it had ever been booted if you do it right. I could do a write up if there is interest but it is super niche use case. Think digital forensics.

I also like this related tutorial from @Kari:

Native boot Virtual Hard Disk - How to upgrade Windows

Specifically, the video right at the start of that tutorial. I wrote myself a little program that fully automates that process. Works like a charm!

Hopachi said:

Yes this works in Hyper-V. You can boot a backup image, from physical disk.
I changed my system SSD drive lately and had the old one around, put it in a USB3 portable case and added it to VM...

The disk has to be offline and then can it be added, in this case via the SCSI controller.

Boots straight to my old desktop.

I couldn't add a usb flash stick to boot though since this cannot be set offline in diskmgmt.

You also have Macrium Reflect's VIboot to boot an image directly in Hyper-V or have it cloned on physical disk to boot as I mentioned.

Hi there
QEMU/KVM Virtual machines can also boot from USB devices -- although if you do that they need to be added to the VM config before re-boot.

After booting USB re-direction allows hot plugging of USB devices -- which IMO is a lot better than HYPER-V.

The other thing about using a "Virtual hard drive" as native boot - you need to use a VHDX format -- QEMU/KVM allows you to use a bog standard Windows NTFS formatted drive as the boot drive .

Cheers
jimbo

Cheers
jimbo

Moriarty said:

kvm-qemu lets you get crazy with block devices. You can for example boot a windows machine to linux. Make a tmpfs ramdisk. Make a qcow write layer in the ramdisk with the physical machine hd as base. Mount that to qemu-nbd service. And on another machine, boot the remote machines hard drive. This would leave no trace on the host system that it had ever been booted if you do it right. I could do a write up if there is interest but it is super niche use case. Think digital forensics.

Hi there
Nice things to play with

Do you work for the CIA for example !!!!!!! or N.Korean Hackers fraternity !!!!!

Cheers
jimbo