--vdev "crypto_null" -- -p 0xf -P -u 0x3 \
--config="(0,0,20),(1,0,20),(2,0,21),(3,0,21)" \
-f /path/to/config_file --transfer-mode poll \
--vdev "crypto_null" -- -p 0xf -P -u 0x3 \
--config="(0,0,20),(1,0,20),(2,0,21),(3,0,21)" \
-f /path/to/config_file --transfer-mode poll \