I’ve made a NAS an an FTP server with my raspberry pi 3 and OSMC.
It works very good but I would like to save all my data (which are that I share with samba) in a second external hard drive and regurlarly with crontab.
I have read a french tutorial and they say that I cannot power the rasp with the µUSB because it restrict the intensity and it cause an I/O error. So they say that we must power by the GPIO. I buy tow stable power supply (5V 2A → 10W then an other 5V 8A → 40W). They can run the rasp but I have a yellow lightning bolt on the right top corner and when i plug just one external hard drive it don’t works, the red LED is blinking. (I haven’t test with the second HDD but I think it will be worst).
Is in fact the intensity restricted too by the GPIO ?
If I’m reading this right, you have an external drive connected to the Pi via USB, and you are trying to power the Pi via a power supply directly connected to the GPIO pins. If that’s so, I don’t think thats a good idea. If I remember correctly, connecting power to the GPIO pins bypasses the fuses in the Pi, so you are in danger to having an Overcooked Pi on your hands
Instead, just get a good quality powered USB hub and connect the external drive to that, and for the Pi’s power, use the original Pi power supply.
That means the input voltage drops below 5V which also means your powersupply is not working as it should.
I suggest you buy the official powersupply from the OSMC store.
But also if you want to run 2 Harddisk on the pi it most likely is best to run them on a powered hub.