diff --git a/weed/stats/metrics.go b/weed/stats/metrics.go
index a46e715c1..36869b7cf 100644
--- a/weed/stats/metrics.go
+++ b/weed/stats/metrics.go
@@ -43,8 +43,6 @@ const (
 	bucketAtiveTTL   = 10 * time.Minute
 )
 
-var readOnlyVolumeTypes = [4]string{IsReadOnly, NoWriteOrDelete, NoWriteCanDelete, IsDiskSpaceLow}
-
 var bucketLastActiveTsNs map[string]int64 = map[string]int64{}
 var bucketLastActiveLock sync.Mutex