How does Optimized Storage work?

I've tried to turn it on, but there was no noticeable effect. I guess it only works when the disk gets full, or when enough time passes, so that the system can figure out which files are rarely used? What is the expected perceiveable effect of the Optimized Storage feature? Will it simply remove unused files (after uploading them to iCloud) and you don't see them locally at all, or it creates kind of zero-sized link files in place of the files and you get the actual file only after you click it, or the optimized file appears totally indistinguishable from the original regular file (name, size, content), but some portions of it (or the entire file) are stored on iCloud and fetched quietly as needed? Are there tools to inspect what files have been optimized and how much optimized?

Replies

I think once you get to low disk space older files will be purged and accessable if you need them via iCloud.

Sorry, this sounds almost as vague as Apple's own advertisement of the feature. It lacks detail and concreteness, in the ways I asked above.


So the question remains. Thanks!

From the Apple site


Storage space maxed out? No problem. macOS Sierra can help make more room by automatically storing rarely used files in the cloud and keeping them available on demand. It can also help you find and remove old files you no longer use. So there’s always room on your Mac for new files and the ones you’ve used most recently.