External Hard Drive question

[HurricaneFan]

I'm looking to buy an external hard drive to hook up to my pi 3. Is it better to get a hard drive that has its own external power adapter, or can the pi power the whole thing fine with just usb power?

[simonster]

I would recommend that you use a hard drive with external power. The Pi3 is already a power hungry device, requiring 5.2v at 2.5amps to work reliably, if you add a hard drive as a load to the USB port, you will increase the power requirements of the Pi significantly.

[HurricaneFan]

@simonster Thanks.

[Starcade2084]

You could check out the hard drives that Western Digital markets for the Raspberry Pi:

http://wdlabs.wd.com/category/wd-pidrive/

...plus, you can get a splitter for the power supply so it's not drawing power through the Pi itself.

[akafox]

Hopefully they will be able to make a one Terabyte micro sd card one day. sigh but for now yes a usb hard drive is the way to go. Besides they are much larger faster and cheaper (as of this writing) than a micro sd card!

@simonster said in External Hard Drive question:

I would recommend that you use a hard drive with external power. The Pi3 is already a power hungry device, requiring 5.2v at 2.5amps to work reliably, if you add a hard drive as a load to the USB port, you will increase the power requirements of the Pi significantly.

Absolutely right. The pi is made to power itself nothing else really. And while they can make single board computers that can power external sata drives well the pi wouldn't be so cheap either!

So here is what I did. I picked up a powered 4-port usb hub ("pluggable" is the name on it) and I got this one because it was known (according to comments) to not back power into the pi. You have to be careful because if you do back power into the pi you can fry it. Then I used an old usb drive I had laying around. Works great! :) (and on a side note no you can not power the pi and the drive from the usb hub..not enough juice)

You'll have to edit the default paths in retropie so that everything can be found but that is easy enough to do. And now that emulationstation handles video snaps you need more space..videos are small..but then again most videos are larger than the games themselves!

(hard to think that a 512 gigabyte mirco sd card is only 150 ..I was happy when I bought my 128 megabyte sd card (mirco wasn't even thought of yet) for 100 for my palm pilot!)

[HurricaneFan]

@akafox So if I buy a big drive, something like 4 Terabytes, how would I know if the drive thats externally powered would send power back to the pi?

[edmaul69]

@hurricanefan a self powered hard drive shouldnt ever back feed. Some hubs do, but i havent had issues with the several hubs i have used on the pi. I wouldnt be too worried about that happening and causing any problems.

[herb_fargus]

@edmaul69 I've had problems with back feeding on the zero but not my pi3

[AkselVolkov]

So, to use external hard drives without own power does not make sense at all? If you take the most common models (like this) https://www.bestadvisers.co.uk/external-hard-drives, then they basically do not have a separate power supply, but they have a good memory and the speed of information exchange is not bad. not comparable with SSD`s, of course, but... Maybe I'm wrong because on the site that gave Starcade I did not find the exact characteristics of the speed of file exchange, only the capacity. So, if the usual external drives have higher capacity and exchange speed, even if they are not designed directly for pi and do not have a separate power supply, is it not better to neglect the not so critical increase in electricity consumption?

[steptoe]

I have a 1TB USB3 portable which uses a 2.5" hard drive. Its tiny and the RPI3 powers it fine. I'm using an official PI power supply but if you can get a good 2.5a power supply that actually gives 5.2v under load you should be ok. Note a good power supply not a £5 copy

The exact same 1TB external hard drive model is also connected to my PS3 and works perfectly, with the PS3 known to have very poor USB support and complaining if anything other than a gamepad is connected to it

The other USB devices such as 5G wireless and keyboard I have running from a powered USB hub with the external 1TB hard drive and two arcade controllers connected to the RPI3. I did have an issue with feedback but solved that but disabling the red wire or +v connector on the USB hub plug stops all power feedback. The hub still works as it should. Not all USB hubs works with the RPI3 thought adding to the frustration, especially the really cheap imported ones

The PI Hut is offering a 7-port powered USB hub that has been confirmed to work perfectly with the RPI3 and has no power feedback. Not cheap at £11 but they guarantee it will work and has a decent power supply

If you intend to use a 4TB external hard drive it will certainly need and should come with its own power supply, but shouldn't cause any problems as it will still be seen as a USB device regardless of size. The only issues it might cause is with installs that insist on FAT32 format if you want one continuous partition only as it will be a GPT drive which is different. MBR drives are a maximum of 2TB partitions, but GPT is pretty much limitless far exceeding current single hard drive sizes. Maximum NTFS volume support apparently tested by Microsoft is 16TB so no issues there !!

FAT32 will NOT format correctly a single partition exceeding 2TB on a GPT drive and WILL only allow a maximum of 2TB and declare the rest as unsed. I know because I've tried it on a 5GB external hard drive. You should be able to format it as FAT32 for 2 partitions without any issues so you can get around it that way and tell the RPI3 that you have 2 partitions labeled as 2 USB drives so it can 'see' them as such

Not sure if its allowed, as its linking to an external site, but this shows you step-by-step how to tell the RPI3 exactly what volumes are mounted by USB and how to access them

I did this method before I realised that the RPI3 has autoboot so does this automatically. Autoboot might not work for multiple partitions though, hence the link to the guide

https://www.modmypi.com/blog/how-to-mount-an-external-hard-drive-on-the-raspberry-pi-raspian

[AkselVolkov]

So, the power source is really such an important point that in no case should not be neglected? And let's say if I want to use an external HD that does not have its own power, then it is desirable to buy a USB hub with its own power supply? But even so, I still can not understand what would be so terrible if the external HD is powered by the pi itself.