Another HDD question - but possibly with a twist this time!

[gzdad]

Hello all,

So, I'm in the same boat of trying to get a 2.5inch HDD working with the Pi and a USB router.

I salvaged the HDD from an old Samsung netbook, and bought a cheap-as USB / SATA cable which has two USB ports on it - one for the data and the other for extra power. I also bought a 10w 2 port USB power block.

I plugged the pi into the power thing, the data bit of the HDD into the Pi, and the power bit into the spare port on the 10w power block.

It all worked pretty well at first, but it's become increasingly unstable. The HDD suddenly stops being recognised, sometimes in mid stream. It's now got to a stage where the HDD is hardly ever recognised - it just sits there making clicking noises.

I've checked the disk in Windows and it has no bad errors or anything.

So, what's the twist? The weird thing is that the pi seems to be able to power itself from the HDD USB input. Which seems very odd.

Anyhow, any ideas on why it's being so weird?

d.

[DaveDriesen]

I think it's acting weird because it is weird

Are you sure there's nothing short circuiting in there? (the disk is drawing power from the power block, and also from the pi, while the pi is also drawing power from the power block and apparently also from the disk?)

Dave Driesen
Linux dev and oldskool elite

[SirLagz]

Is this a quality 10W USB power supply ?
It sounds like the hard drive is not getting enough power...

[TheShryke]

I think I see your problem, if your usb to sata is anything like mine then those two cables aren't data + power, they are both power, so its trying to draw power from both usbs but its not getting a steady amount from both. Is your 10w usb thing a hub? if so then just plug both connectors in there, if not, my advice would be get a powered hub

[gzdad]

Really helpful!

The answer is as you say: the HDD was not getting enough power because both the connectors were power connectors and it was getting an uneven amount of power. The back-feeding to the pi was a red herring.

I bought a four-point unpowered USB hub which had an extra USB dongle for power. I plugged the extra USB power bit into my USB power brick, turning it into a powered hub. I think plugged the data bit into the pi, and both of the HDD bits into the now-powered 4 port hub. This seems to have flattened out the power supply to the HDD and it now runs without a hitch.

I would upload a photo but I can't quite seem to find out how to do it!

Thanks all, really really helpful. Massively appreciated...