zero_buffers If this option is given, fio will init the IO buffers to
all zeroes. The default is to fill them with random data.
+refill_buffers If this option is given, fio will refill the IO buffers
+ on every submit. The default is to only fill it at init
+ time and reuse that data. Only makes sense if zero_buffers
+ isn't specified, naturally.
+
nrfiles=int Number of files to use for this job. Defaults to 1.
openfiles=int Number of files to keep open at the same time. Defaults to