diff --git a/raft/node.go b/raft/node.go
index 59d61284d..22332be6b 100644
--- a/raft/node.go
+++ b/raft/node.go
@@ -38,7 +38,7 @@ var (
 // SoftState provides state that is useful for logging and debugging.
 // The state is volatile and does not need to be persisted to the WAL.
 type SoftState struct {
-	Lead      uint64
+	Lead      uint64 // must use atomic operations to access; keep 64-bit aligned.
 	RaftState StateType
 }