setup backup pipeline

hosts/desktop/hardware-configuration.nix

@@ -34,6 +34,7 @@
   };
 
   services.btrbk = {
+      extraPackages = [ pkgs.lz4 ];
       instances = {
           hf = {
               onCalendar = "hourly";
@@ -56,6 +57,32 @@
                   };
               };
           };
+          bak = {
+              onCalendar = "daily";
+              settings = {
+                  stream_compress = "lz4";
+                  incremental = "yes";
+                  snapshot_create = "no";
+                  snapshot_dir = "@snapshots";
+                  timestamp_format = "long";
+
+                  snapshot_preserve_min = "all";
+                  target_preserve_min = "no";
+                  target_preserve = "2m 4w";
+
+                  ssh_identity = "/etc/btrbk/ssh/id_ed25519_btrbk_nas";
+                  ssh_user = "btrbk";
+                
+                  volume =  {
+                      "/mnt/snapshots/root" = {
+                          subvolume = {
+                              "@home" = {};
+                          };
+		          target = "ssh://jupiter.home.opel-online.de:2220/mnt/snapshots/Mars/@snapshots/@hades";
+                      };
+                  };
+	      };
+	  };
       };
   };