Hi Andrey, >Covered in the FIO HOWTO under rw and percentage_random options. I tried this configuration but when i run, it doesn't do that expected. [global] ioengine=posixaio invalidate=0 norandommap ramp_time=5 iodepth=8 runtime=60 time_based direct=1 numjobs=1 group_reporting filesize=100M blocksize=8k percentage_random=12,8 <= 12% seqread, 8% seqwrite rw=randrw rwmixread=70 <= 70% randread and 30% randwrite for others [hdisk10] stonewall filename=/dev/rhdisk10 Regards, Thierry -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html