ntfy-alerts: suppress notifications for sanoid

modules/ntfy-alerts.nix

@@ -97,6 +97,11 @@ in
         };
       };
 
+      # TODO: sanoid's ExecStartPre runs `zfs allow` which blocks on TXG sync;
+      # on the hdds pool (slow spinning disks + large async frees) this causes
+      # 30+ minute hangs and guaranteed timeouts. Suppress until we fix sanoid
+      # to run as root without `zfs allow`. See: nixpkgs#72060, openzfs/zfs#14180
+      "sanoid".unitConfig.OnFailure = lib.mkForce "";
     };
 
     # Global OnFailure drop-in for all services
@@ -105,6 +110,12 @@ in
         [Unit]
         OnFailure=ntfy-alert@%p.service
       '')
+
+      # Sanoid-specific drop-in to override the global OnFailure (see TODO above)
+      (pkgs.writeTextDir "etc/systemd/system/sanoid.service.d/onfailure.conf" ''
+        [Unit]
+        OnFailure=
+      '')
     ];
     # ZED (ZFS Event Daemon) ntfy notification settings
     services.zfs.zed = {