diff --git a/lustre/tests/replay-single.sh b/lustre/tests/replay-single.sh
index 3f03f382c2d53fc828f3fc6078ee2f691d216cef..fa99f52e150313162a095df7a51c3206e361aa79 100755
--- a/lustre/tests/replay-single.sh
+++ b/lustre/tests/replay-single.sh
@@ -1513,6 +1513,10 @@ at_start()
         # speed up the timebase so we can check decreasing AT
 	do_facet mds "echo 8 >> $at_history"
 	do_facet ost1 "echo 8 >> $at_history"
+
+	# sleep for a while to cool down, should be > 8s and also allow
+	# at least one ping to be sent. simply use TIMEOUT to be safe.
+	sleep $TIMEOUT
     fi
 }