I haven't tried that particular test, but I've had a ZFS drive filled to the brim. I just deleted a bunch of files and was back to normal. This was on a compute

I haven't tried that particular test, but I've had a ZFS drive filled to the brim. I just deleted a bunch of files and was back to normal. This was on a computer with a single pool, also used for booting. The system didn't even crash or anything.