The idea is still around! Apple’s APFS file system (and HFS+in its later days) support sort-of transparent compression, and on all its platforms most system files - the ones that don’t change much - are compressed to save space for user files. There’s surprisingly little documentation about this.
Btrfs has compression as well. It compressed my root partition to a third of it’s size. It helps out with some games as well, but they usually are not as compressible. The performance impact is pretty minimal as long as you don’t set the compression level excessively high.
The idea is still around! Apple’s APFS file system (and HFS+in its later days) support sort-of transparent compression, and on all its platforms most system files - the ones that don’t change much - are compressed to save space for user files. There’s surprisingly little documentation about this.
There’s a third party tool you can use to compress files yourself: https://github.com/RJVB/afsctool
It looks like the technical details are in this pdf: https://developer.apple.com/support/downloads/Apple-File-System-Reference.pdf
Btrfs has compression as well. It compressed my root partition to a third of it’s size. It helps out with some games as well, but they usually are not as compressible. The performance impact is pretty minimal as long as you don’t set the compression level excessively high.