Limit "diffdisk" size

[Mrazator]

Is it possible to somehow limit the "diffdisk" size?

Using lima as docker host on M1 and the size of ~/.lima/docker/diffdisk takes up to 49.01 GB.

• Is all of it really used?
• Is it possible to prune it somehow?
• What is is inside?

[jandubois]

You can configure the maximum size of the diffdisk when you create the Lima instance via the disk setting in lima.yaml:

lima/examples/default.yaml

Lines 38 to 40 in 2b88071

	# Disk size
	# 🟢 Builtin default: "100GiB"
	disk: null

The space is mostly used for container images; you can delete old images, but the space will not be returned to the host, it will only be reused for new images. You have to delete and recreate the instance to get the disk space back.

Issue #356 is about trimming the disk space (after pruning images), but it is not implemented, and I think it isn't clear if this is even possible on macOS.

[afbjorklund]

Does the trick to copy the VM image with qemu-img convert work on macOS ?

It needs to be shut down before attempting, though. It usually works on Linux

[afbjorklund]

What is is inside?

I think it has some docker system df command ?

https://docs.docker.com/engine/reference/commandline/system_df/