Hi!

I have an Odroid XU4, which I intend to use as server, which is running 24/7. The operating system is an Ubuntu 14.04 LTS server and lives on an SD card. I'd like to use a HDD for data storage purposes, so I bought 1TB Western Digital blue codename WD10EZEX and a Captiva rack, which has an asmedia ASM1053 chip in it.

My problem is when I power on the external HDD (with its power button), then it does not spin, but after plugging into the USB3 port of the Odroid, it spins up and seems to spin infinitely, or at least does not spin down after 20 minutes. I'd like the HDD to spin up only if I need files from it, so most of the time it is idle, and I don't like the idea that an idle HDD consumes the same amount of power as a HDD which is in usage. Is there anything I can do to fix this?

According to other forums: http://forum.hddguru.com/viewtopic.php?f=1&t=29531&start=20&mobile=mobile WD HDD-s are special, which are not necessarily affected by hdparm. I assume by USB racks the idle spindown time depends on the rack and the operating system as well, but I am not certain of that. I'd like to know more about the topic, because I am not sure which hardware or software component I need to configure to solve this problem.

Actually I found out, that this inifinite spin behavior is present only if the server does not run or the USB cable is unplugged. Otherwise the HDD spins down after 10 minutes. So I assume that Ubuntu controls this process. Since the server will run 24/7 I think I won't do anything about this.