diff --git a/internal/backend/local/local.go b/internal/backend/local/local.go
index be332e8ad..d6bdef1e4 100644
--- a/internal/backend/local/local.go
+++ b/internal/backend/local/local.go
@@ -148,6 +148,13 @@ func (b *Local) Save(_ context.Context, h restic.Handle, rd restic.RewindReader)
 		}
 	}(f)
 
+	// preallocate disk space
+	if size := rd.Length(); size > 0 {
+		if err := fs.PreallocateFile(f, size); err != nil {
+			debug.Log("Failed to preallocate %v with size %v: %v", finalname, size, err)
+		}
+	}
+
 	// save data, then sync
 	wbytes, err := io.Copy(f, rd)
 	if err != nil {