> Does a filesystem that never deletes/overwrites anything exist? > Obviously once space runs out it would start overwriting the oldest versions. You can’t ha

> Does a filesystem that never deletes/overwrites anything exist? > Obviously once space runs out it would start overwriting the oldest versions. You can’t have both. Also, your system wouldn’t prevent data loss on hardware failures. What you describe is/may be a WORM device (https://en.wikipedia.org/wiki/Write_once_read_many https://en.wikipedia.org/wiki/Write_once_read_many)