VirtualBox - Enabling encryption allocates all dynamic storage

[Ceph92]

So, if I create VM with 50gb dynamic drives, and only use 20gb, why does enabling encryption permenantly expand the .VHD file to 50gb? This is a win10 guest on win10 host.

So, even if I decrypt the VDI file, it stays at 50gb. If I compact the file, it still stays at 50gb.

Any ideas?

 

[Stugots]

Pretty sure that's a limitation of how thin provisioning in VirtualBox works.

Just an FYI, I hope this is for personal/home use. Disk Encryption requires the Extension Pack which is only free for personal/home use, and Oracle DOES monitor the IP's that is downloaded from.

 

[k1pp3r]

Sounds right. Encryption is a block level task most of the time, so its going to scan/encrypt all blocks on the entire disk. When that block is encrypted, the disk is expanded.

 

[kdh]

thin provisioning goes right out the window with guest level encryption at the hypervisor level. suckage. only way around it is to have a disk subsystem that does the encryption for you so by the time its presented to your hypervisor, your hypervisor doesn't know about it, and doesn't care. that's where thin provisioning will work as expected.

 

[danswartz]

Sounds right. Encryption is a block level task most of the time, so its going to scan/encrypt all blocks on the entire disk. When that block is encrypted, the disk is expanded.

Yeah. I remember being annoyed trying to back up my wife's work laptop, which had mandatory block-level encryption. She was only using 20% or so of the hard drive, but nope, 128GB of backup file. And no way to do incrementals either