For rhel 6 see tuned and tuned-adm View the sheduler used to write to disk.cat /sys/block/sda/queue/scheduler Set the scheduler to write directly to io device without delay. should do that for SANecho noop > /sys/block/sda/queue/scheduler To have it persistent at reboot add the following to grub.confelevator=noop When testing for performance don't forget to clear the cache firstcat /proc/sys/vm/drop_caches free sync echo 3 > /proc/sys/vm/drop_caches free