Unable to mount my new external HDD

Troubleshooting
1

Hi there!

I have an issue mounting my new Seagate One Touch 5TB HDD (Model: STKC5000400). I have a Raspberry Pi 4. Booting from a USB flash drive, an additional USB hub is connected and that has an external power source. There’s another 4TB HDD connected directly to the Pi’s USB 3 port. Both HDD is formatted exFAT. I’m able to mount my small 750GB WD drive on the Pi, I’m assuming the new HDD has a higher power consumption. The whole thing, the Pi and the USB hub is powered through a 10A 5V power source. I’ve measured the cable that’s sources power to the USB hub, it’s stable ~5V.
After disconnecting the Seagate drive, I was able to boot the Pi. I ran

dmesg -l err,crit,alert,emerg

and this is the output:

root@MediaServer:~# dmesg -l err,crit,alert,emerg
[    0.513640] bcm2708_fb soc:fb: Unable to determine number of FBs. Disabling driver.
[    2.340444] sd 0:0:0:0: [sdb] No Caching mode page found
[    2.340460] sd 0:0:0:0: [sdb] Assuming drive cache: write through
[   52.911385] usb 2-1.2: device not accepting address 4, error -62
[   63.919386] usb 2-1.2: device not accepting address 4, error -62
[   74.927384] usb 2-1.2: device not accepting address 4, error -62
[   85.935386] usb 2-1.2: device not accepting address 4, error -62
[   85.936096] sd 1:0:0:0: rejecting I/O to offline device
[   85.936138] sd 1:0:0:0: [sda] Asking for cache data failed
[   85.936163] sd 1:0:0:0: [sda] Assuming drive cache: write through
[   96.943393] usb 2-1.2: device not accepting address 6, error -62
[  107.951384] usb 2-1.2: device not accepting address 7, error -62
[  119.215384] usb 2-1.2: device not accepting address 8, error -62
[  130.223381] usb 2-1.2: device not accepting address 9, error -62
[  130.224052] usb 2-1-port2: unable to enumerate USB device
[  171.359530] hwmon hwmon1: Undervoltage detected!
[  179.423764] hwmon hwmon1: Undervoltage detected!
[  213.699548] hwmon hwmon1: Undervoltage detected!
[  231.839833] sd 1:0:0:0: [sda] Asking for cache data failed
[  231.839848] sd 1:0:0:0: [sda] Assuming drive cache: write through
[  243.935732] hwmon hwmon1: Undervoltage detected!
[  255.551887] sd 1:0:0:0: [sda] Asking for cache data failed
[  255.551901] sd 1:0:0:0: [sda] Assuming drive cache: write through

I don’t understand the under voltage message. I don’t think that should be an issue, the 10 Ampers power source should be enough. Any thoughts?

2

Well, basically USB ports of a RPI4 are not designed to power external drives like HDD/SSD. There are physical limitation on the amount of power the USB ports can provide together. Especially during boot/startup this can be easily exhausted. Therefore we highly recommend to power each external drive via an own PSU or a powered USB hub. Therefore the under voltage messages are not surprising.

3

The new external drive is connected to a externally powered USB HUB. The 4 TB drive works perfectly on the Pi’s USB port.

4

But you get a undervolt warning, so it seems it works not so perfectly as you think :wink:

The error message “device not accepting address” could come from the USB hub. Some hubs use additional protocols to handle power saving methods (power down each port individually). But it could be also caused just by a faulty cable or a variety of other reasons. You could try to connect the HDD directly to another port (maybe after booting, when the other drive has not so high power draw anymore.
What hub do you use exactly?