diff --git a/src/ior.h b/src/ior.h
index 015d111..ad543ff 100755
--- a/src/ior.h
+++ b/src/ior.h
@@ -179,6 +179,8 @@ typedef struct
     char*       URI;                 /* "path" to target object */
     size_t      part_number;         /* multi-part upload increment (PER-RANK!) */
     char*       UploadId; /* key for multi-part-uploads */
+    int         collective_md;       /* use collective metatata optimization */
+ 
 
     /* RADOS variables */
     rados_t rados_cluster;           /* RADOS cluster handle */