diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 230fca104..c0bdcdf96 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -10,6 +10,9 @@ import (
 )
 
 func (v *Volume) garbageLevel() float64 {
+	if v.ContentSize() == 0 {
+		return 0
+	}
 	return float64(v.nm.DeletedSize()) / float64(v.ContentSize())
 }