feat(etna): add postgresql backups

systems/etna/default.nix

@@ -1,6 +1,5 @@
 {
   lib,
-  pkgs,
   config,
   _utils,
   ...
@@ -28,6 +27,10 @@ in
     secrets.generate
     cfTunnelSecret.generate
 
+    # essential configs, do not remove
+    ./postgresql.nix
+
+    # services
     ./cobalt.nix
     ./dendrite.nix
     ./forgejo.nix
@@ -59,11 +62,6 @@ in
     openssh.openFirewall = true;
     nginx.enable = true;
 
-    postgresql = {
-      enable = true;
-      package = pkgs.postgresql_16;
-    };
-
     frp = {
       enable = true;
       role = "client";

systems/etna/postgresql.nix

@@ -0,0 +1,19 @@
+{ pkgs, ... }:
+{
+  services = {
+    postgresql = {
+      enable = true;
+      package = pkgs.postgresql_16;
+
+      port = 5432;
+      enableTCPIP = true;
+    };
+
+    postgresqlBackup = {
+      enable = true;
+      backupAll = true;
+      compression = "zstd";
+      location = "/data/backups/postgresql";
+    };
+  };
+}