Additionally, (almost all) Unix filesystems do not fragment under normal use. This is far superior to FAT, which does have this problem, but also means that the

Additionally, (almost all) Unix filesystems do not fragment under normal use. This is far superior to FAT, which does have this problem, but also means that there's typically no way to defragment them short of recreating them. A nearly-full disk is not "normal use" in the above sense.