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1# NixOS {#sec-nixos-state}
2
3## `/nix` {#sec-state-nix}
4
5NixOS needs the entirety of `/nix` to be persistent, as it includes:
6- `/nix/store`, which contains all the system's executables, libraries, and supporting data;
7- `/nix/var/nix`, which contains:
8 - the Nix daemon's database;
9 - roots whose transitive closure is preserved when garbage-collecting the Nix store;
10 - system-wide and per-user profiles.
11
12## `/boot` {#sec-state-boot}
13
14`/boot` should also be persistent, as it contains:
15- the kernel and initrd which the bootloader loads,
16- the bootloader's configuration, including the kernel's command-line which
17 determines the store path to use as system environment.
18
19
20## Users and groups {#sec-state-users}
21
22- `/var/lib/nixos` should persist: it holds state needed to generate stable
23 uids and gids for declaratively-managed users and groups, etc.
24- `users.mutableUsers` should be false, *or* the following files under `/etc`
25 should all persist:
26 - {manpage}`passwd(5)` and {manpage}`group(5)`,
27 - {manpage}`shadow(5)` and {manpage}`gshadow(5)`,
28 - {manpage}`subuid(5)` and {manpage}`subgid(5)`.