I think LVM or DM provide snapshot and compression capabilities which you could layer under ext4. I like ext4 for being simple and fast and having options to t

I think LVM or DM provide snapshot and compression capabilities which you could layer under ext4. I like ext4 for being simple and fast and having options to turn off the unnecessary stuff. It's great for gigabytes of caches, tempfiles, build artifacts, scratch files etc. The bookkeeping and indirection needed for those features would be a waste of CPU cycles for shortlived data.