# NixOS {#sec-nixos-state}

NixOS itself obviously needs `/nix` to be persistent, so the system environment
can be linked from the nix store during activation.

Moreover, `/boot` should also be persistent, as it contains the kernel, initrd,
and the command-line determining the system environment's path in the nix store.


## Users and groups {#sec-state-users}

- `/var/lib/nixos` should persist: it holds state needed to generate stable
  uids and gids for declaratively-managed users and groups, etc.
- `users.mutableUsers` should be false, *or* the following files under `/etc`
  should all persist:
  - {manpage}`passwd(5)` and {manpage}`group(5)`,
  - {manpage}`shadow(5)` and {manpage}`gshadow(5)`,
  - {manpage}`subuid(5)` and {manpage}`subgid(5)`.