Set -leveldbFlushOnMutate to false by default.

storage/raw/leveldb/leveldb.go

@@ -23,7 +23,7 @@ import (
 )
 
 var (
-	leveldbFlushOnMutate     = flag.Bool("leveldbFlushOnMutate", true, "Whether LevelDB should flush every operation to disk upon mutation before returning (bool).")
+	leveldbFlushOnMutate     = flag.Bool("leveldbFlushOnMutate", false, "Whether LevelDB should flush every operation to disk upon mutation before returning (bool).")
 	leveldbUseSnappy         = flag.Bool("leveldbUseSnappy", true, "Whether LevelDB attempts to use Snappy for compressing elements (bool).")
 	leveldbUseParanoidChecks = flag.Bool("leveldbUseParanoidChecks", true, "Whether LevelDB uses expensive checks (bool).")
 )