title: Raspberry Pi can't control HDD spin downs and idle time
body: <p>I'm running MPD on a Raspberry Pi connected to an USB HDD Dock over USB. The HDD Is formatted in BTRFS and I mount a subvolume (-o subvol=Music,autodefrag,space_cache,compress,relatime). Unfortunately i can't control the HDD's spin downs. The HDD spins down and goes to stand by after approx. 30 secs. </p>
  
  <p>I've already tried <strong>HDPARM</strong> with: </p>
  
  <blockquote>
    <p>hdparm -B 254 -S 0 /dev/sda</p>
  </blockquote>
  
  <p>And <strong>HD-IDLE</strong> with: </p>
  
  <blockquote>
    <p>hd-idle -i 0 -a sda -i 1200 </p>
  </blockquote>
  
  <p>with no effect.</p>
  
  <p>As a dirty trick i moved the mpd's log file to the external HDD and revved up MPD's log verbosity (but this is not reliable). Currently i'm running an infinite loop to keep the drive alive.</p>
  
  <p>I need some advice how to regulate this issue.</p>