Pre-converting qcow2 image for faster LXD VM creation

[TCB13]

@Igorgro

The more interesting question is why LXD doesn’t use the full power of qcow2 images?

@stgraber

99% of LXD users are either using zfs or btrfs, both of which are copy on write filesystems, so that part of QCOW2 becomes redundant. Both of those also support compression, making that part of QCOW2 similarly redundant.

Yes, I might be wrong, but qcow2 has a very big advantage for VMs, that is managing pre-allocation. Raw images might be great but if you’ve 100 VMs set to 20GB each that doesn’t scale very well.

Or is there a way to get VMs in btrfs and raw images to not pre-allocate the space?

Thank you.