> Who says your filesystem isn't compressing data under you?

Me, because we don't use transparent compression anywhere.

> Actually, who says the disk itself isn't?

I'm not very sure about that, to be honest. SSDs do that to prolong their life, but the saved space doesn't return as more space on FS level. It just returns as endurance, which is more important in my case.

So, disk's transparent compression doesn't mean very much from a sysadmin/OS operations perspective.

> Me, because we don't use transparent compression anywhere.

Since Fedora 34, a clean install will result in btrfs with zstd compression turned on. (An update of an older install will of course not change the filesystem from underneath the files.)

I generally don't reinstall my OS unless it breaks. My current Debian installation is around 8 years old at this point (it's updated, of course), reinstalled to migrate it to amd64.

Other systems we install are configured on many levels, so even if the defaults are BTRFS w/zstd, it might be either known or changed to suit our needs better.

That's why i use Slackware - does not try to be smart.