{...}: {
  environment.persistence = {
    "/srv" = {
      hideMounts = true;
      directories = [
        "/etc/nixos"
        "/var/log"
        "/var/lib/postgresql"
        "/var/lib/acme"
        {
          directory = "/var/lib/nix-sync";
          user = "nix-sync";
          group = "nix-sync";
          mode = "0700";
        }
        {
          directory = "/var/lib/sshd";
          user = "root";
          group = "root";
          mode = "0755";
        }
      ];
      files = [
        "/etc/machine-id"
      ];
    };
  };
}