[sootzoo]

I really had problems going this route (Ubuntu host with Windows guest). While the guest ran in VB reasonably well, trying to snapshot a baseline image and generally use VBox differencing disks quickly ran me out of space on the host SSD.

Even with a 256GB drive and a number of tweaks like hosting the Windows pagefile and temp from a passthrough disk, disabling Windows automatic updates, and using an immutable disk containing the OS install/multi-attach for copy-on-write behavior, VBox still used a ton of space to track the differences from my baseline snapshots. Even starting the VM quickly consumed 10-20GB in the new disk image. Was hard to conclude anything other than it wasn't a viable "dual workstation" setup and I capitulated and moved to Windows 10.

Sucks, because it was really quite nice to have a unix under the hood, though WSL makes this a bit more tolerable in Win 10 AU.

[pizza234]

It's inappropriate to target space saving when it comes virtualization, as it's not what hypervisors are designed for - if so, a hypervisor would have to interpret the underlying FS calls, and optimize them space-wise. Besides, I think pretty much all the formats behave the same; qcow2 for example, does not optimize on the fly the writing of zeros.

All in all though, if you ultimately moved to a native Windows 10, therefore allocated X space of native disk, the space requirement is not different from having only a virtualized one with X space of virtualized disk (heck, you could even pass a partition).

Having said that, if 10-20 GB of space are taken so quickly on boot, it may be worth investigating (you could even vim the diff disk), but I find your claim somewhat misleading, as you're likely experiencing this on the first absolute boot after taking then snapshot, but not on the subsequent ones; therefore, if your system steadily takes 20+20 GB of space, that's a perfectly reasonable requirement.

[robocat]

A 512GB SSD is minimum for multi-VM dev. I have Ubuntu host and ran out of space after a few VM's on 256GB. I wasted a lot of time(money) trying to slim down the Windows installs, a few hours&dollars to upgrade SSD was good investment ...