diff --git a/tests/test_heal.sh b/tests/test_heal.sh
index c5308751..319e9a58 100755
--- a/tests/test_heal.sh
+++ b/tests/test_heal.sh
@@ -46,8 +46,8 @@ kill_osds()
 kill_osds &
 
 LD_PRELOAD="build/src/libfio_vitastor.so" \
-    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=4k -direct=1 -iodepth=16 -fsync=256 -rw=randwrite \
-        -refill_buffers=1 -mirror_file=./testdata/mirror.bin -etcd=$ETCD_URL -image=testimg -loops=10 -runtime=120
+    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bsrange=4k-128k -direct=1 -iodepth=32 -fsync=256 -rw=randrw \
+        -randrepeat=0 -refill_buffers=1 -mirror_file=./testdata/mirror.bin -etcd=$ETCD_URL -image=testimg -loops=10 -runtime=120
 
 qemu-img convert -S 4096 -p \
     -f raw "vitastor:etcd_host=127.0.0.1\:$ETCD_PORT/v3:image=testimg" \