Hi Sam,
Thank you for your detailed response which was really helpful and interesting.
By the way, my 2TB drive is actually a USB key/thumb drive that turned out to be a chinese fake. I managed to use f3 to re-partition it to it’s actual usable capacity of 29GB. It still doesn’t auto-mount in OSMC on my Pi 1 Model B.
Anyway, I also have a Pi 3B+ that I can start using instead of the Pi1 Model B. At raspberrypi.org they say the Pi 3B+ can supply a maximum of 1200mA to downstream USB peripherals. This forum post states there are: "…no per-port limits (which means all 1.2A can come out of a single port if no other USB ports are in use). "
I have searched a lot trying to get detailed numbers of the amperage drawn from the Pi by an attached USB 2.5" self-powered drive when idling, under load and when spinning up. This thread used an in-line usb voltage tester to record amps drawn by a WD Passport Ultra and reported idling (0.22A) and under load (0.42A). I’m not sure about spin-up but a WD support forum thread states: “If using a WD Passport , or WD Elements Portable 2.5” hard drive, please ensure that the computer’s USB ports supply at least 650 milliamps through the USB ports. "
I would like to avoid having too many power supplies if I could. Do you think those numbers above suggest it could be reasonable to have OSMC on a Pi 3B+ with a single attached 2.5" self-powered external usb drive to store all media? I’m thinking of getting a Western Digital 4 TB My Passport Portable USB drive and plug it directly into the Pi 3B+. Would this set-up really be a borderline case, with potential to cause data loss, as you described above?
If you still don’t think it’s worth the risk then would you happen to know of any Powered USB hubs that can also power a Pi so only one power supply/plug/outlet is needed? Maybe the D-Link DUB-H7/B 7-Port USB 2.0 Hub can power a Pi and its peripherals? The manufacturer of the Plugable USB 2.0 7-Port Hub claim that it can: “Power the Raspberry Pi and its attached USB devices”. There is even a hackster.io project where someone made such a device themselves so I guess it can be done. What do you think about all this?
Cheers,
Flex