Implement option vmtype to select between raw or qcow2

[paulmenzel]

[paulmenzel]

I'm not yet convinced that we should support this from within grml-debootstrap, tbh. :)

You write:

It looks like though, installing the system into that file using NBD is twice as slow.

So what's the actual reason, to not install it into raw format as-is, and then convert to the format as needed?

I only came up with this, because on the “build machine” you do not always have 100 GB of free space for the raw image.

Also all the qemu-nbd actions around /dev/nbd0 seem to ask for trouble AFAICS, what about e.g. if the device is used elsewhere already? :-/ (Not commenting on other code changes themselves yet)

Yes, I have to figure out – the same with kpartx – how to get the correct device.