want fio to use placement identifier only at indices 0, 2 and 5 specify
``fdp_pli=0,2,5``.
-.. option:: md_per_io_size=int : [io_uring_cmd]
+.. option:: md_per_io_size=int : [io_uring_cmd] [xnvme]
Size in bytes for separate metadata buffer per IO. Default: 0.