When having backup jobs that persist to a removable device like an external HDD, the directory shouldn't be created by an activation script as this might confuse auto-mounting tools such as udiskie(8). In this case the job will simply fail, with the former approach udiskie ran into some issues as the path `/run/media/ma27/backup` was already there and owned by root.
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at http://nixos.org/nixos and in the manual in doc/manual.