diff --git a/lustre/tests/replay-ost-single.sh b/lustre/tests/replay-ost-single.sh
index 3f0d50404ec43c3bf3036a28d8ed4957378f78e8..6561a5d821c69a637119a7415c9ecff45d2c3a08 100755
--- a/lustre/tests/replay-ost-single.sh
+++ b/lustre/tests/replay-ost-single.sh
@@ -157,7 +157,8 @@ test_5() {
 	if (( size > GB )); then
 		size=$GB
 	fi
-	local iozone_opts="-i 0 -i 1 -i 2 -+d -r 4 -s $size -f $TDIR/$tfile"
+	# no random I/O (-i 2) as it's very slow with ZFS
+	local iozone_opts="-i 0 -i 1 -+d -r 4 -s $size -f $TDIR/$tfile"
 
 	iozone_bg $iozone_opts &
 	local pid=$!