rw, offset, length
where with rw=0/1 for read/write, and the offset
and length entries being in bytes.
+ write_iolog=x Write an iolog to file 'x' in the same format as iolog.
+ The iolog options are exclusive, if both given the
+ read iolog will be performed.
lockmem=x Lock down x amount of memory on the machine, to
simulate a machine with less memory available. x can
include k/m/g suffix.