diff --git a/ocaml/xcp-rrdd/bin/rrdd/xcp_rrdd.ml b/ocaml/xcp-rrdd/bin/rrdd/xcp_rrdd.ml
index 455723633bb..bb0285b4b18 100644
--- a/ocaml/xcp-rrdd/bin/rrdd/xcp_rrdd.ml
+++ b/ocaml/xcp-rrdd/bin/rrdd/xcp_rrdd.ml
@@ -292,7 +292,7 @@ let dss_mem_vms doms =
           | Ok mem ->
               Some
                 ( Rrd.VM uuid
-                , Ds.ds_make ~name:"memory_internal_free" ~units:"B"
+                , Ds.ds_make ~name:"memory_internal_free" ~units:"KiB"
                     ~description:"Dom0 current free memory"
                     ~value:(Rrd.VT_Int64 mem) ~ty:Rrd.Gauge ~min:0.0
                     ~default:true ()