+mirror command line option would be --iodepth 2 or --iodepth=2. You can
+also use the command line for giving more than one job entry. For each
+--name option that fio sees, it will start a new job with that name.
+Command line entries following a --name entry will apply to that job,
+until there are no more entries or a new --name entry is seen. This is
+similar to the job file options, where each option applies to the current
+job until a new [] job entry is seen.