Also this doesn't just mean more disk space usage, but also longer local build times... for the app I'm working on `exporting to image` takes 71.5 seconds with containerd, without containerd it's 4.3s (the rest of the build takes ~180 seconds). And that's just a 5.76GB image.
That's almost certainly nothing to do with the change. Please report this if you can with commands used.
Buildkit isn't changing behavior here.
Internally in docker there is a shim to make the legacy storage behave like containerd snapshotters (as well as it can, anyway--not perfect due to hard to resolve issues in the old storage).
But it still kept both the compressed and uncompressed versions of images.
