Virtualbox from physical hard drive

[Don B. Cilly]

Please forgive the ignorance. I have perused the forums and FAQs, but you know how it is with searches.

I currently use two OSs: Mint 18:02 and Kubuntu 14.04.
I use Mint 18 because K14 is going fast out of date. But I much prefer the latter.

So I thought, well easy peasy: I boot the Mint, have K14 in a VM in the other desktop (or the other way around), best of both worlds, right?
Because, easy peasy, I tell the VM to use the current K14 installation on the other HD, right?

Well, wrong, it looks like.
Because if I tell it that, it says the disk is not bootable. Which of course, it is.
It seems to me it wants me to make some sort of image of the system and use that.
Rather cilly, methinks, as it's a huge installation containing years of software and various stuff.

What an I missing?

[socratis]

I currently use two OSs: Mint 18:02 and Kubuntu 14.04.

On the same disk/different partitions, or on two disks? How do you choose what to boot? If on one disk, is it MBR or GPT?

if I tell it that, it says the disk is not bootable

If you tell who, and how exactly do you tell it?

[Don B. Cilly]

Well, as I said,
> I tell the VM to use the current K14 installation on the other HD

I have Kubuntu on /dev/sda and Mint on /dev/sdb. The boot loader is on sda.

if you tell who, and how exactly do you tell it?

The VM ;·)
When I press Start, it asks me what to use as a boot medium.
I tell it - browse to - /sdb3, it accepts it, then opens a window, which is where I presume the VM is supposed to run, with an error message to the effect that it's not a bootable disk.

I could give you more precise details - I have the VM on the other system - but... I'd like to know, is it supposed to work by pointing to an actual separate physical hard disk to boot or does it have to be a virtual one/image/whatever?

[socratis]

When I press Start, it asks me what to use as a boot medium. I tell it - browse to - /sdb3

I'm afraid that's not how it works. I wish it was that simple. What you're looking for is a really advanced feature called "raw disk access". Read the process in ch. 9.9.1. Using a raw host hard disk from a guest and come back with any questions. Please note that there's a big fat warning coming with that feature.

What's impressive though is that VirtualBox accepted /dev/sdb as a bootable medium. That sounds like a bug to me. It should NOT accept it.

[Don B. Cilly]

I wish it was that simple.

Yeah, well, so do I :·)
I mean, apologies again, I'm quite new to VMs, I just thought, that would be a great way to run my different OSs at the same time - with all my data on them.
I see it's probably not what VMs are meant for.
I guess they're just meant to look at OS and see how pretty - or ugly - they are... or something :·)

Please note that there's a big fat warning coming with that feature.

I see. "Most importantly, do not attempt to boot the partition with the currently running host operating system in a guest."

Well, I was planning to boot another partition - on another disk and all...
Still, "Incorrect use or use of an outdated configuration can lead to total loss of data on the physical disk"... is just too scary as it is.
As if the rest of it wasn't complicated enough ;·)
I'll just reboot the OSs back and forth.
Thanks anyway.

What's impressive though is that VirtualBox accepted /dev/sdb as a bootable medium. That sounds like a bug to me. It should NOT accept it.

Well, it accepted - let be browse to it - as a medium, then it said it wasn't bootable.

[socratis]

I'll just reboot the OSs back and forth.

Great call! At least for the moment...

Thanks anyway.

No problemo...