dd of=file if=/dev/zero bs=512 count=1000000 dd of=file if=/dev/zero bs=512 count=1000000 oflag=direct sync; echo 3 > /proc/sys/vm/drop_caches cd /usr/local/bin curl -O https://raw.githubusercontent.com/cxcv/iops/master/iops chmod a+rx iops iops /dev/sdb iops /dev/sda dd if=file of=/dev/null dd if=file iflag=direct of=/dev/null dd if=/dev/sda of=/dev/null dd if=/dev/sdb dd if=/dev/sdb of=/dev/null iostat -xmt 1 /dev/sda cat /sys/block/sdb/queue/max_sectors_kb echo "1024" > /sys/block/sdb/queue/max_sectors_kb blktrace -d /dev/sda -o - | blkparse -i -