Create Differencing disk?

[spamme0]

I lost my VBOX in a system upgrade, but have the virtual disk archives.
I reinstalled 2.1.4 and can't figure out how to run it.

In the older version, when you set up a virtual disk, you had the option
to create a differencing drive based on another base drive.
That option has disappeared and I can't figure out how to create one.
I've read tutorials on immutable drives. There's much discussion
on whether or not the new data is lost when the machine is closed.
And it's not at all clear to me how to do immutability anyway...

I have a baseline win2k .vdi. I want to create multiple machines
based on this baseline. Is there a tutorial that describes in detail
how I do this in 2.1.4?
Thanks, mike

[Sasquatch]

I think you mean "cloning". That function is still available, but due to the added functionality of full compatibility with VHD and VMDK, it might not work as it should. There are some work arounds here, like a normal file copy, then run VBoxManage internalcommands sethduuid <filename> on the copy.

[spamme0]

Thanks, but cloning is not what I want.
I want a BIG .vdi baseline file and several tiny
differencing disks for different applications based
on the BIG baseline file. I don't have the disk space
to make 'em clones.
This worked great in a previous version, but I can't remember which version.
All you had to do was click the box when creating the virtual disk.
Guess I'll have to try 'em all.

Don't know what the lawyers say, but cloned drives probably demand
individual licenses. If you have only one base windows installation,
one might argue that you need only one license....maybe...

[marnold]

Thanks, but cloning is not what I want.
I want a BIG .vdi baseline file and several tiny
differencing disks for different applications based
on the BIG baseline file. I don't have the disk space
to make 'em clones.
This worked great in a previous version, but I can't remember which version.
All you had to do was click the box when creating the virtual disk.
Guess I'll have to try 'em all.

I think this is what you want to do....

• Create the base image.
  defragment and then zero the free space
  If you aren't running the latest version you might be able to compact the VDI using "VBoxManage"
  Release the base image and delete from the "Virtual Media Manager" (Select "Keep" so you don't delete the physical file)
  "attrib +r <Image VDI>" or "chmod a-r <Image VDI>" depending on window/linux host
  Reattach VDI as immutable "VBoxManage openmedium disk <Image VDI> -type immutable"

Now when you attach the drive VirtualBox will auto-magically attach a differencing disk for everything that happens from this point on. My tutorial (see below) will also show how to create branched differencing disks from a differencing disk created on top of an immutable base OS image.

Branching differencing disks requires a snapshot to be taken of the machine being used as the template and then skipping disk creation during the creation of a new machine wizard. You can attach a disk in the "Settings" dialog which has the option of "Show differencing disks". If you select this option, you will then be able to select the base differencing disk from which you want to branch.

I think this should answer your question.

Don't know what the lawyers say, but cloned drives probably demand
individual licenses. If you have only one base windows installation,
one might argue that you need only one license....maybe...

I think this depends on what you are using the branches for. If you never run them both at the same time (I'm lucky - or unlucky as the case may be - in that I can't cos I don't have the hardware ). Maybe I should check my MSDN license agreement but I think that covers me for 10 installs.

Hope this helps. I am currently constructing a few blog posts on how to do this and will write it up as a full tutorial for posting here too http://mikesspacewithin.blogspot.com/.

[mpack]

Don't know what the lawyers say, but cloned drives probably demand
individual licenses.

If it's Microsoft you are talking about, then they would probably "demand" individual license fees regardless of the actual legal position.

Anyway, I personally don't see a substantial technical difference between a backup image of a physical PC hard drive, and a "clone" of a virtual hard drive. True, if you actually run both images at the same time then you may be in murkier waters... except if both are still on the same physical CPU, its still one CPU, one license... so that angle is debateable too IMHO.

In my case I already had an XP license for my home PC, and I bought a second one to use in VMs. The separate "vm license" giving me what I feel is the moral right to carry VMs between PCs. Having bought two licenses - to be used mostly on one physical PC, I do believe I've paid Microsoft their due!

[spamme0]

Thanks, I'll give it a shot.
mike