diff --git a/example/zfs-over-legacy.nix b/example/zfs-over-legacy.nix
index e55c0d4..273975b 100644
--- a/example/zfs-over-legacy.nix
+++ b/example/zfs-over-legacy.nix
@@ -1,3 +1,4 @@
+# systemd will mount an ext4 filesystem at / and zfs will mount the dataset underneath it
 {
   disko.devices = {
     disk = {