====== hdparm ======
  * http://en.wikipedia.org/wiki/Hdparm
  * http://prohardver.hu/tema/milyen_winchestert_vegyek_3/hsz_32468-32468.html
  * https://sites.google.com/site/disablehddapm/

  * Energiagazdálkodás kikapcsolása: <code bash>
hdparm -B 255 /dev/sda
</code>


<blockquote>
  * Display information of the hard drive: <file bash>
hdparm -I /dev/sda
</file>
  * Turn on DMA for the first hard drive: <file bash>
hdparm -d1 /dev/sda
</file>
  * Test device read performance of the first hard drive: <file bash>
hdparm -t /dev/sda
</file>
  * Enable energy saving spindown after inactivity (24*5=120 seconds): <file bash>
hdparm -S 24 /dev/sda
</file>
  * To retain hdparm settings after a software reset, run: <file bash>
hdparm -K 1 /dev/sda
</file>
  * Enable read-ahead: <file bash>
hdparm -A 1 /dev/sda
</file>
  * If the disk is constantly too noisy, you can change its acoustic management at the cost of read/write performance:<file>
hdparm -M 128 /dev/sda
</file>
  * If the disk synchronisation intervals are too short, then even small amounts of data will be written to disk which can have severe consequences for its lifespan. The better way would be to collect small data into bigger chunks and wait until the chunk is big enough to be written to disk.\\ Current web browsers like Chrome write regularly small chunks when browsing in order not to lose any important data when the application crashes. However, this lets the disk spin very often as the drive repeatedly needs to unleash and then park its heads. The generated noises can be thus regarded as distracting by the user. To circumvent this issue, you can switch the drive to the lowest degree of power management (next value, 255, turns power management off): <code bash>
hdparm -B 254 /dev/sda
</code> Additionally, changing the value of ''/proc/sys/vm/dirty_expire_centisecs'' can have an effect on the performance. It sets the flush interval when dirty pages are written to disk.

<note tip>Note that all these commands are only effective in the long-run, if you make the changes persistent. However, the settings you can set via ''hdparm'' are reverted each time you reboot. Therefore, it might be wise to restore the personal settings upon boot. An appropriate place that exists in most Linux distributions is the ''/etc/rc.local'' script.</note>
</blockquote>