Odroid HC4 harddrives head parking

    Quote from Da Flex

    Theory: HDD loses power supply on reboot for a very short time, which causes a HDD reboot and a strange noise.

    Measurement to proof that theory: Find the power supply pins of the HDD by having a look at the data sheet. Remove some isolation of the connecting cable to get measure points at those power supply pins. Then connect a voltage measure instrument, and check the needle while rebooting. If the needle moves down, the theory has been proofed.

    well, I'm sure the PSU isn't the root cause. I even bought more powerful unit, instead of default 15V 3A I bought 15V 4A, just to be sure it can provide plenty of juice. the root cause is obviously combination of the HDD manufacturer and Linux way of shutting down the drives. but I understand what you want to tell me. and also I don't think I would be able to measure anything useful this way. that may be so short time when power is cut, that voltmeter won't show actually the drop in the voltage.

    It's a question of coltage, not current.

    According to the USB 2.0 Standard chapter 7.2.2 the minimal allowed device input voltage is 4.5V if even connected to a high powered host. No HDD/SSD is designed to operate with this.

    • Official Post

    HC4 is powered using a barrel jack (15V-4A) and the drives are connected via standard SATA connectors, not USB. This device was designed to be a NAS device and HardKernel have been designing this kind of things for years (not the first cloudshell design/product they sell) so while testing for voltage drop is something to do - I'd be surprised if it's the reason.

    I did shut down the drive with "hdparm -Y /dev/sda2" command, heard it turn off and after I ran "reboot" command it immediately turned the drive back on following by the squeaky drive reboot sequence.
    am I missing something about how to properly shut down the drive?

    • Official Post
    Quote from toml

    I did shut down the drive with "hdparm -Y /dev/sda2" command, heard it turn off and after I ran "reboot" command it immediately turned the drive back on following by the squeaky drive reboot sequence.
    am I missing something about how to properly shut down the drive?

    I think you did it right. Too sad it didn't worked. That's the only "head parking" option I know - there are no real head parking commands available.

    Current theory: The OS is reading the master boot record on reboot. That shouldn't happen on shutdown. Can you please check that (the sound on shutdown)?

    well, I think I give up. I anyway want it 24x7 turned on, so some heads parking on shutdown/reboot shouldn't bother me. except that it supposed to run as a KODI box, so I'll need to invest my time in learning python and creating my own plugin re-mapping power button on remote to start the "turn-off" screensaver and suspend all playback, immitating shutdown/suspend action for my wife and son, because they love pushing remote controls' power buttons...
    if something like this exists already, please let me know so I won't waste my time. thanks.

    no need. it spins down on its own after a time of inactivity. seems like some kind of internal power management. spin down is ok, little noisier, but ok, I'd say. what wasn't was this additional wakeup, after it went off during reboot, just in the moment the power is cut to the hard drive. and as nobody else has this issue, I'd say it's Seagate specific. so beware of Seagate drives.