treewide: snapshot important datasets with sanoid

common/default.nix

@@ -10,6 +10,7 @@
     ./nginx.nix
     ./nix.nix
     ./openssh.nix
+    ./sanoid.nix
     ./security.nix
     ./steam.nix
   ];

common/sanoid.nix

@@ -0,0 +1,35 @@
+{ config, pkgs, inputs, ... }:
+
+{
+  config = {
+    services.sanoid = {
+      enable = true;
+      extraArgs = [ "--verbose" ];
+
+      # Local snapshots for important datasets
+      templates."production" = {
+        yearly = 0;
+        monthly = 3;
+        daily = 30;
+        hourly = 36;
+        autosnap = true;
+        autoprune = true;
+      };
+
+      # Reduced-retention version for datasets that are backed up to the NAS
+      templates."safe" = {
+        yearly = 0;
+        monthly = 0;
+        daily = 7;
+        hourly = 24;
+        autosnap = true;
+        autoprune = true;
+      };
+
+      # datasets."rpool_sggau1/reese/system" = {
+      #   useTemplate = [ "safe" ];
+      #   recursive = "zfs";
+      # };
+    };
+  };
+}