Add firestar btrbk config

firestar/btrbk.nix

@@ -0,0 +1,42 @@
+{ pkgs, ... }:
+
+let
+  volumeConfig = (subvolumes: {
+    snapshot_dir = "@snapshots";
+    subvolume = builtins.foldl'
+      (acc: subvol: acc // {
+        ${subvol} = { };
+      })
+      { }
+      subvolumes;
+  });
+in
+{
+  services.btrbk = {
+    sshAccess = [
+      {
+        key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHTqU3EvTgY5/e9m6YyQWypQPK58t9iPmPnPYAvnODGB asonix@lionheart";
+        roles = [ "source" "info" "send" ];
+      }
+    ];
+    extraPackages = with pkgs; [ gzip ];
+    instances.btrbk = {
+      onCalendar = "hourly";
+      settings = {
+        snapshot_preserve_min = "2d";
+        snapshot_preserve = "7d 5w";
+        transaction_log = "/var/log/btrbk.log";
+        volume = {
+          "/btrfs/hdd" = volumeConfig [
+            "@documents"
+            "@downloads"
+            "@music"
+            "@pictures"
+            "@videos"
+          ];
+          "/btrfs/nvme" = volumeConfig [ "@development" ];
+        };
+      };
+    };
+  };
+}

firestar/default.nix

@@ -8,6 +8,7 @@
   imports =
     [
       # Include the results of the hardware scan.
+      ./btrbk.nix
       ./hardware-configuration.nix
       ./wireguard.nix
     ];