Mixed 70/30 read-write fio

Realistic mixed workload 70% read / 30% write; closer to OLTP than pure tests

fio --name=mixed --filename=/data/testfile --size=8G --rw=randrw --rwmixread=70 --bs=4k --iodepth=32 --numjobs=4 --runtime=120 --time_based --direct=1 --group_reporting