{
  environment.persistence."/nix/persist" = {
    enable = true;
    hideMounts = true;
    directories = [
      # logs
      "/var/log"
      "/var/lib/systemd/coredump"

      # users
      "/var/lib/nixos"

      # private ssh keys
      "/etc/ssh"

      # mailserver
      "/var/vmail"
      "/var/dkim"
      "/var/lib/dovecot"
      "/var/lib/postfix"
      "/var/lib/postgresql"
      "/var/lib/redis-rspamd"
      "/var/lib/roundcube"
      "/var/lib/secrets"
    ];
    files = [
      "/etc/machine-id"
    ];
  };
}